My friend and I did Baseball Furies at Dragoncon a few years ago. It's a pretty easy costume to do that still looks cool. I'm in the back with the yellow face paint with a family of Furies I ran into. My friend and I bought plain jerseys from Eastbay and had the Furies logo airbrushed on the back, though the Mondo Tees ones are nice too. For some reason I remember black stirrup socks being difficult to find, but the rest was pretty painless.
There was a group at Dragoncon last year that had representatives from a bunch of gangs from The Warriors, but I missed it. They even had Luther with the clinking beer bottles... But at least we got to mock fight some Jedi.