One of my nuttier friends wears a:
PETA - People Eating Tasty Animals!
T-shirt in SF - he gets some wild reactions!!!
;-)
DD
Not quite on the same level...but when my brother lived in SF, he joined the NRA in spite of the fact that he doesn't own any guns (yet), just so he could claim to be a member and wear an NRA hat around.
It didn't get him too many friendly glances.