Half the fun in San Francisco takes place outdoors. If you're not in the mood to trek it, there are other things to do that allow you to enjoy the surroundings.

Ballooning

Although you must drive an hour to get to the tour site, hot-air ballooning over the Wine Country is an ethereal experience. Adventures Aloft, P.O. Box 2500, Vintage 1870, Yountville, CA 94599 (tel. 800/944-4408 or 707/944-4408), is Napa Valley's oldest hot-air balloon company, staffed with full-time professional pilots. Groups are small, and each flight lasts about an hour. The cost of $210 per person includes a post-adventure champagne brunch and a framed "first-flight" certificate. Flights launch daily at sunrise (weather permitting).

Beaches

Most days it's too chilly to hang out at the beach, but when the fog evaporates and the wind dies down, one of the best ways to spend the day is oceanside in the city. On any truly hot day, thousands flock to the beach to worship the sun, build sandcastles, and throw the ball around. Without a wet suit, swimming is a fiercely cold endeavor and is not recommended. In any case, dip at your own risk -- there are no lifeguards on duty and San Francisco's waters are cold and have strong undertows. On the South Bay, Baker Beach is ideal for picnicking, sunning, walking, or fishing against the backdrop of the Golden Gate (though pollution makes your catch not necessarily worthy of eating).

Ocean Beach, at the end of Golden Gate Park, on the westernmost side of the city, is San Francisco's largest beach -- 4 miles long. Just offshore, at the northern end of the beach, in front of Cliff House, are the jagged Seal Rocks, inhabited by various shorebirds and a large colony of barking sea lions (bring binoculars for a close-up view). To the left, Kelly's Cove is one of the more challenging surf spots in town. Ocean Beach is ideal for strolling or sunning, but don't swim here -- tides are tricky, and each year bathers drown in the rough surf.

Stop by Ocean Beach bus terminal at the corner of Cabrillo and La Playa to learn about San Francisco's history in local artist Ray Beldner's whimsically historical sculpture garden. Then hike up the hill to explore Cliff House and the ruins of the Sutro Baths. These baths, once able to accommodate 24,000 bathers, were lost to fire in 1966.

Biking

The San Francisco Parks and Recreation Department maintains two city-designated bike routes. One winds 7.5 miles through Golden Gate Park to Lake Merced; the other traverses the city, starting in the south, and continues over the Golden Gate Bridge. These routes are not dedicated to bicyclists, who must exercise caution to avoid crashing into pedestrians. Helmets are recommended for adults and required by law for kids under 18. A bike map is available from the San Francisco Visitor Information Center, at Powell and Mason streets, for $3, and from bicycle shops all around town.

Ocean Beach has a public walk- and bikeway that stretches along 5 waterfront blocks of the Great Highway between Noriega and Santiago streets. It's an easy ride from Cliff House or Golden Gate Park.

Avenue Cyclery, 756 Stanyan St., at Waller Street, in the Haight (tel. 415/387-3155), rents bikes for $7 per hour or $28 per day. It's open daily, April through September from 10am to 7pm and October through March from 10am to 6pm. For cruising Fisherman's Wharf and the Golden Gate Bridge, your best bet is Blazing Saddles (tel. 415/202-8888), which has five locations around Fisherman's Wharf. Bikes rent for $28 per day, including maps, locks, and helmets; tandem bikes are available as well.

Boating

At the Golden Gate Park Boat House (tel. 415/752-0347) on Stow Lake, the park's largest body of water, you can rent a rowboat or pedal boat by the hour and steer over to Strawberry Hill, a large, round island in the middle of the lake, for lunch. There's usually a line on weekends. The boathouse is open daily from 10am to 4pm, weather permitting.

Cass' Marina, 1702 Bridgeway, Sausalito; P.O. Box 643; Sausalito, CA 94966 (tel. 800/472-4595 or 415/332-6789), is a certified sailing school that rents sailboats measuring 22 to 38 feet. Sail to the Golden Gate Bridge on your own or with a licensed skipper. In addition, large sailing yachts leave from Sausalito on a regularly scheduled basis. Call or check the website for schedules, prices, and availability of sailboats. The marina is open Wednesday through Monday from 9am to sunset.

City Stair Climbing

Many health clubs have stair-climbing machines and step classes, but in San Francisco, you need only go outside. The following city stair climbs will give you not only a good workout, but seriously stunning neighborhood, city, and bay views as well. Check the Stairways of San Francisco on the Sister Betty website for more ideas.

Filbert Street Steps, between Sansome Street and Telegraph Hill, are a particular challenge. Scaling the sheer eastern face of Telegraph Hill, this 377-step climb winds through verdant flower gardens and charming 19th-century cottages. Napier Lane, a narrow, wooden plank walkway, leads to Montgomery Street. Turn right and follow the path to the end of the cul-de-sac, where another stairway continues to Telegraph's panoramic summit.

The Lyon Street Steps, between Green Street and Broadway, were built in 1916. This historic stairway street contains four steep sets of stairs totaling 288 steps. Begin at Green Street and climb all the way up, past manicured hedges and flower gardens, to an iron gate that opens into the Presidio. A block east, on Baker Street, another set of 369 steps descends to Green Street.

Fishing

Berkeley Marina Sports Center, 225 University Ave., Berkeley (tel. 510/237-3474), makes daily trips for ling cod, rock fish, and many other types of game fish year-round, and it makes trips for salmon runs April through October. Fishing equipment is available; the cost, including boat ride and bait, is about $80 per person. Reservations are required, as are licenses for adults. One-day licenses can be purchased for $11 before departure. Find out the latest on the season by contacting their hot line at tel. 510/486-8300 (press 3). Excursions run daily from 6am to 4pm. Fish are cleaned, filleted, and bagged on the return trip for a small fee (free for salmon fishing).

Golf

San Francisco has a few beautiful golf courses. One of the most lavish is the Presidio Golf Course (tel. 415/561-4661). Greens fees are $60 until 12:30pm for residents Monday through Thursday and $96 for nonresidents; rates drop to $50 until 2pm, then to $35 for the rest of the day for residents and nonresidents. Friday though Sunday, rates are $96 for residents and $108 for nonresidents from 8 to 11am; from 11am to 12:30pm, the cost is $60 for residents. After that it's $50 for everyone until 2pm and $35 for the rest of the day. Carts are included. There are also two decent municipal courses in town.

The 9-hole Golden Gate Park Course, 47th Avenue and Fulton Street (tel. 415/751-8987), charges greens fees of $14 per person Monday through Thursday, $18 Friday through Sunday. The 1,357-yard course is par 27. All holes are par 3, and this course is appropriate for all levels. The course is a little weathered in spots, but it's casual, fun, and inexpensive. It's open daily from sunup to sundown.

The 18-hole Lincoln Park Golf Course, 34th Avenue and Clement Street (tel. 415/221-9911), charges greens fees of $31 per person Monday through Thursday, $36 Friday through Sunday, with rates decreasing after 4pm in summer, 2pm in winter. It's San Francisco's prettiest municipal course, with terrific views and fairways lined with Monterey cypress and pine trees. The 5,181-yard layout plays to par 68, and the 17th hole has a glistening ocean view. This is the oldest course in the city and one of the oldest in the West. It's open daily at daybreak.

Handball

The city's best handball courts are in Golden Gate Park, opposite Seventh Avenue, south of Middle Drive East. Courts are available free, on a first-come, first-served basis.

Parks

In addition to Golden Gate Park and the Golden Gate National Recreation Area, San Francisco boasts more than 2,000 acres of parkland, most of which is perfect for picnicking or throwing around a Frisbee.

Smaller city parks include Buena Vista Park (Haight St. between Baker and Central sts.), which affords fine views of the Golden Gate Bridge and the area around it and is also a favored lounging ground for gay lovers; Ina Coolbrith Park (Taylor St. between Vallejo and Green sts.), offering views of the Bay Bridge and Alcatraz; and Sigmund Stern Grove (19th Ave. and Sloat Blvd.) in the Sunset District, which is the site of a famous free summer music festival.

One of my personal favorites is Lincoln Park, a 270-acre green on the northwestern side of the city at Clement Street and 34th Avenue. The Legion of Honor is here, as is a scenic 18-hole municipal golf course. But the best things about this park are the 200-foot cliffs that overlook the Golden Gate Bridge and San Francisco Bay. To get to the park, take bus no. 38 from Union Square to 33rd and Geary streets, then walk a few blocks.

Running

The ING Bay to Breakers Foot Race (tel. 415/359-2800) is an annual 7.5-mile run from downtown to Ocean Beach. About 80,000 entrants take part in it, one of San Francisco's trademark events. Costumed participants and hordes of spectators add to the fun. The event is held on the third Sunday of May.

The San Francisco Marathon takes place annually in the middle of July. For more information visit their website (no phone contact).

Great jogging paths include the entire expanse of Golden Gate Park, the shoreline along the Marina, and The Embarcadero.

Tennis

The San Francisco Parks and Recreation Department (tel. 415/753-7001) maintains more than 132 free courts throughout the city. Almost all are available free, on a first-come, first-served basis. An additional 21 courts are available in Golden Gate Park, which cost $5 for 90 minutes during weekdays and $10 on weekends. Check the website for details on rules for reserving courts.

Walking & Hiking

The Golden Gate National Recreation Area offers plenty of opportunities. One incredible walk (or bike ride) is along the Golden Gate Promenade, from Aquatic Park to the Golden Gate Bridge. The 3.5-mile paved trail heads along the northern edge of the Presidio out to Fort Point, passing the marina, Crissy Field's new restored wetlands, a small beach, and plenty of athletic locals. You can also hike the Coastal Trail all the way from the Fort Point area to Cliff House. The park service maintains several other trails in the city. For more information or to pick up a map of the Golden Gate National Recreation Area, stop by the park service headquarters at Fort Mason; enter on Franklin Street (tel. 415/561-4700).

Although most people drive to this spectacular vantage point, a more rejuvenating way to experience Twin Peaks is to walk up from the back roads of U.C. Medical Center (off Parnassus) or from either of the two roads that lead to the top (off Woodside or Clarendon aves.). The best time to trek is early morning, when the city is quiet, the air is crisp, and sightseers haven't crowded the parking lot. Keep an eye out for cars, however, because there's no real hiking trail, and be sure to walk beyond the lot and up to the highest vantage point.

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