Paintball is a sport where the participants use markers to shoot paintballs (roughly marble-sized, .68 caliber, gelatin capsules filled with colored polyethylene glycol "paint") at other players. For more info see: Paintball - Wikipedia
The Gotchaspielfeld arena is located 12km across the Czech border from Germany - on the road to Pilsen. This is about 2½ hours drive from Munich - Autobahn almost all the way.
The game fields were tested by the magazine Gotcha! Paintball-Action (November 2004 edition) and awarded a total rating of 9.9 out of 10. Some photos from the field:

There are five large playing fields, each with a different theme. These are Hamburger Hill, Tank Woodland, Chop Suey Camp, The Factory, and Amazon.
A one-day package costs €55. This includes overalls, a marker, battle pack, protective mask, gas canister, 200 paintballs, and lunch. A two day package costs €80 and includes gear as above plus a second lunch. Extra paintballs can be bought for €20 for 500.
The € Euro currency can be used throughout the field. English is spoken by the staff - in fact, the field ownership is British.
What you should bring with you: good humour - most important. And suitable clothing - sweatshirt and jeans or jogging trousers, and possibly gloves too. That's it.
Random factoid: in England more people play paintball than they do golf or tennis.
Enquiries and bookings can be made via...Gotchaspielfeld s.r.o. CZ
Podnikatelsky Areal
CZ 348 02 Bor - Vysocany
Tel.: +49 (0) 84 5273 2040
Website: Gotchaspielfeld