We know: you're stuck at work and want to go home. Get this weekend started. Or are already dreading the melancholia you'll feel come Monday night knowing that the three-day weekend is over.
Relax. Here's a brief list of things to do that don't involve you going out of town (because, really, the City is at its best during three-say weekends; everyone leaves): Carnaval (Mission; fiesta, forever), Opera in the Park (Dolores Park; arias, et al.), Capsule Design Festival (Hayes Valley; design street fair), Artist In Residence Program at SF Recycling & Disposal (SF Dump; art, garbage), Masturbate-a-thon (Center for Sex & Culture; massive circle jerk, basically), Authentic Memorial Day Parade (Presidio Park; former soldiers, "freedom").
For more details on the aforementioned merriment, or to find out what else is going on, check out 71Miles for events happening in and around the Bay Area.
Know of something going on? Well then, lets us know in the comments section, OK? OK.