Here are some links to a few online paintball games:
I had brought up a game at our last meeting, apperantly the RPG game that is like Mafia Wars, Mobster, Vampire Wars, etc..., has been pulled offline for some reason.
First Person Shooter: http://www.candystand.com/play/paintball-smash#
Stationary First Person Shooter: http://www.snopi.com/freetime/assault.swf
Flash based Shooter: http://www.miniclip.com/games/paintball/en/