Former SF resident still in the area here, SF has great food.
http://www.redhotchillipepperca.com/ - Indo-Chinese restaurant in San Carlos (walkable from San Carlos CalTrain station, easy to get the SF terminal)
They have a Ghost Fire Chicken in spicy ghost pepper sauce. The flavor itself isn't all that great, but it is hot. They make you sign a waiver.
As far as stuff in SF, you have to hit The Buena Vista Cafe for an Irish coffee. Scoma's is a seafood spot nearby, they have fantastic fish. It's not on the menu anymore, but you can still order Diplomatica - it's basically a mixed seafood linguine in a white wine cream and garlic sauce that is to die for.
The Giants are shitty this year so tickets are cheap, the stadium is amazing.
Tonga Room and Smuggler's Cove are cool spots for tropical drinks.
If you like beer hit Toronado - make sure you know what you want by the time you get to the register, it's like the Soup Nazi from Seinfeld.
Southern Pacific Brewing Company is a cool spot to hang out and get some brews, it's in a big converted warehouse.
There are also several Off the Grids in different locations on different days. There is one on Friday nights at Fort Mason and I think Saturday afternoon in the Mission. Might be others as well. Tons of food trucks show up and you get get really good stuff like steamed pork buns, Korean pork belly tacos, and all kinds of other stuff.
There are hundreds of great spots in SF, feel free to shoot me a PM if you are looking for anything specific.
Cheers,
Austin