I just stumbled -- well, I walked in and stumbled out -- across what may be one of the best happy hours in the city. The Waterfront Cafe -- happy hour 3-7 every day. $5 well drinks, $3 draft beer (Anchor Steam, Sierra Nevada and something else), I think the wine was $5, too. Nice selection of bar bites, all $5 or less, including 99 cent oysters. Spacious, lovely views of the Bay, super nice people -- extra points for having coat hooks and purse hooks under the bar.
I ended up ordering the traditional combo of burger and fries, that is, I ordered the two mini sliders ($5) and the truffle parmesan fries ($3). The fries were close to perfect: medium cut, piping hot, crisp on the outside, fluffy on the inside, just enough truffle oil and a light sprinkle of parmesan. I offered to share them with the women next to me at the bar (it was a generous serving). They demurred. I insisted they try. One ate one and said to her friend "you have to try one!" The sliders were notable not only for being good, but for the attention that went into them: the small patties were thick enough to be lightly pink in the middle, had a slightly smoky char (I saw a wood oven, they may have a wood grill as well -- ETA: website says mesquite grill), a thin slice of cheddar cheese, sitting on a half slice of what looked to be a decent tomato (I don't eat tomatoes, but it was red and juicy-looking, not pink and cottony) and a cornichon skewered to the top of the brioche bun, plus there was a nice little pile of salad on the side -- not a lettuce garnish, but an actual pile of dressed greens. I would definitely go back for happy hour and would be interested in trying them for dinner (and isn't that one of the reasons for having happy hour? I love a restaurant that "gets" how to cultivate customers).
Just to say it again: Happy hour 3 to 7 every day! 99 cent oysters and $3 Anchor Steam on tap.
7 Pier, San Francisco, CA 94111
***caveat*** I work at this bar!!!!!
Lava Lounge (527 Bryant Street between 4th and 3rd). It's usually pretty slow on Mondays and Tuesdays and has a 20% off everything happy hour from 5 - 7pm. It's pretty nice inside considering the neighborhood is rather run down and industrial but there is usually meter parking unless there's something happening at the ballpark.
The food is pretty good - most people are surprised at the quality of the food. The owner runs a catering business out of the kitchen that does weddings and events at City Hall - so the food is better than people think.
There's a lounge area in the back of the bar with seating. Calling around 4pm with a heads up is a good idea.
Nihon Whisky Lounge does a fantastic Happy Hour from 5:30 to 7:00 daily. 1/2-off cocktail menu drinks and appetizer menu items. For a group of 20, you would have to make reservations for the room upstairs. Parking has its challenges but it's not too painful or impossible.
Nihon Whisky Lounge
1779 Folsom Street, San Francisco, CA 94103