Things to Do

There's a lot to do in San Francisco.  Maybe too much to do in a week, but here's a short list to start things off:

Golden Gate Bridge If you're in San Francisco, you have to visit the Golden Gate Bridge.
Alcatraz This link is for the ferry boat to Alcatraz, but has information on the famous prison.
Nike Missile Site One of the most jaw-dropping historical places in the Bay.  Decommissioned nuclear missile site that served as the last line of defense during the Cold War.  Located in the Marin Headlands near Fort Baker about 30 minutes north of San Francisco, but only open on Wednesday to Saturday from 12:30 to 3:30 pm.
Fisherman's Wharf This place screams tourist trap, but it is a landmark and there are a few good things here.
Ghirardelli Square Historic chocolate factory converted into a shopping center.
San Francisco Maritime National Historic Park
USS Pampanito Submarine Exhibit and Museum World War II submarine docked at Fisherman's Wharf that is both an exhibit and museum.
The Embarcadero
Coit Tower Located in Telegraph Hill is a monument dedicated to San Francisco's firefighters.
Chinatown The largest Chinatown outside of Asia.
Lombard Street As seen in a few Clint Eastwood movies, that's the crazy, curving street in San Francisco.

Crissy Field Old Army airfield converted to a park by the beach and with a great view of the Golden Gate.
Palace of Fine Arts Historic rotunda next to Crissy Field and the Exploratorium.
Fort Point Old fort at the southern base of the Golden Gate Bridge.
Fort Mason Historic pier that served as the point of embarkation for American troops in World War II.  Now a cultural center that hosts various activities.
The Presidio Old Army fort that was the home of Coastal Artillery branch, now a national park.
Baker Beach Long stretch of beach on the western end of the Presidio.
China Beach Small cove near the start of Land's End.  Old legend has it that Chinese fishermen would lay anchor and camp on the beach.
Land's End Cliff side trail that starts at Eagle's Point and ends near the Cliff House.
The Cliff House This is the historic restaurant rebuilt with three restaurants in one: The Zinc Bar/The Bistro Restaurant, Sutro's, and the Terrace Room (Sunday brunch).
Golden Gate Park Home to the De Young Museum, California Academy of Sciences, Conservatory of Flowers, Strybing Arboretum, Japanese Tea House and Garden, Buffalo Paddock, and more.
Ocean Beach One of the longest stretches of beach, but don't go in the water.  Riptides, strong currents, and hypothermic water make it hazardous for even strong swimmers and surfers.
Fort Funston Good place to go hang gliding or walk your dog.
Fort Baker Former Army post on the north side of the Golden Gate Bridge.  Home to Cavallo Point Lodge and the Bay Area Discovery Museum.
Muir Woods National park dedicated to trees.  About 45 minutes north of San Francisco.

For the historians:
Legion of Honor Located near Land's End in Lincoln Park, built in honor of the soldiers from California who died in World War I.
SFMOMA or San Francisco Museum of Modern Art.

For the sports fan and participant:
AT&T Park, Home of the San Francisco Giants
San Francisco 49ers Made famous by Coach Steve Walsh, Quarterback Joe Montana and the West Coast Offense now struggling to get back into contention with a new Head Coach, GM, and Quarterback.
Stanford University Sports Catch a football or basketball game during the college seasons.
Golden State Warriors The Bay's basketball team, home court in the East Bay next to the Coliseum.
Oakland Raiders Coach John Madden and Tom Flores brought glory and a Championship to Oakland, but the team has struggled to do so since they left.
University of California Athletics  Catch a football or basketball game during the college season.
San Jose Sharks The Bay's hockey team that's always a bridesmaid never a bride, makes it to the playoffs almost every year but never to the Stanley Cup.
Infineon Raceway Watch NASCAR or drive the track yourself (not during the race, of course).  Located in the North Bay.
Bay to Breakers You can run nude, just don't run drunk.  Run 7.46 miles (12 km) across San Francisco City from the Bay at the Embarcadero to the Breakers at the Great Highway in Golden Gate Park.  
San Francisco Marathon The start point and finish point is at the Ferry Building.
Escape from Alcatraz Triathlon No prisoner has ever escaped Alcatraz alive, but of thousands racers can swim from Alcatraz, bike, and run to freedom.

For the kids:
California Academy of Sciences This is also for the big kids (especially when they open it at night), but little kids will like this place.
San Francisco Zoo
Aquarium of the Bay Located in Fisherman's Wharf

Union Square
Westfield San Francisco Centre