You should look into Airsoft then. It's military simulation with pellet guns, and some games run entire weekends. There are different goals (depending on the organizers - some are just basic CTF) and all are encouraged to make the game as realistic as possible (i.e. smoke bombs, uniforms, unit-style tactics/movement). It's also based on honor, so if you get hit, you call yourself out. There is usually a regeneration period of some length and then you're back in the game. Check www.airsoftplayers.com or www.cimmerians.com for more information.