Blood and Body of Christ. Sangria with a Communion wafer.
Goofball events like Bring Your Own Bigwheel are what made me fall in love with San Francisco in the first place. This is old-school San Francisco weirdness, and the fact that things like this still periodically happen here is one of the major factors that still makes it worth putting up with all the ways in which this city has gotten worse over the last few years. This event is just so hilarious, stupid, and a little dangerous. My face hurts from smiling so much!
I've gone to this every year for the last 8 years or so, and I think that in only two or three of those years have I managed to convince any of my friends to come along.
All of my friends hate fun, you see.