I went paintballing today for someone's birthday.
It was horrible / fun. Filthy and rainy and evil.
When they hit you its like you've just been slapped by a giant wooden hand and it stings like a knob for about 5 minutes, then nothing.
And right at the last match, I was hiding behind some trees, and my goggles steamed up, but I could make out a yellow gun (I was on red team). So me and this other lad waited til we had him in our sights, and then absolutely peppered him with about 10 shots.
But then he started screaming really high pitch "AAAAAAAAAAGH, HELP HELP HELP!!!!" and it turned out he was only about 12. I felt horrible. :(
Paintballing. Hugely over-rated, but 'enjoyable' nonetheless.