Paintball is one of the best sports to play. It may hurt, but the adrenaline pumping through your body dulls the sharp pains. The best way to do this and cheapest is to gather as many friends and equipment as you can, find an open area in a forest or an enclosed area, set up a course giving enough cover for each team. These are my favorite markers out there (paintball guns) http://www.paintballguns.net/Kingman/Paintball_Guns/. There are a lot of places that have courses already set up, but they are usually expensive http://www.skirmish.com/.
Image via: pain4glory.com
activity-creativity 