I recently learned that in the small town of Laughlin, NV, there was a bigass battle between the Hell's Angels and the Mongols involving up to 100 combatants.
http://en.wikipedia.org/wiki/River_Run_Riot
I think someone should totally make an Avalon Hill style tactical boardgame of that battle. Each player would have a certain number of points to purchase gang members, individual weapons, and "upgrades" for their gang members such as meth. You could then have an indoor tactical battle with slot machines and gaming tables being the terrain.