Why don't you be different, just like everybody else?
Bay to Breakers is a 7.6 mile footrace celebrated every third Sunday in May. Participants wear the most outrageous costumes (and sometimes, lack thereof). Nudity is prohibited but not enforced. It was started in 1912 to lift the city's spirits after the 1906 earthquake. It's essentially a huge party with some 65,000 participants, with people of all shapes and sizes (ahem).
Race starts off at the Embarcadero and ends inside the Golden Gate Park. Lot's of traditions on this annual event. Those discs flying at the starting line are actually tortillas. There is another small group wearing huge salmon costumes running 'upstream' is called Breakers to Bay.
I've always been wanting to go but only managed to for the first time this year. Also If you watch closely, you will see one team wearing the infamous orange CPDRC Inmate costume on one of the street corners. It's also the first time I've heard of the Ramones' I Wanna Be Sedated played with an accordion!
Had a memorable time. Even bumped into a San Francsico icon, the real Frank Chu on our way back to the car. He just crossed the finish line as we were leaving apparently.