we should totally have a jazz jackrabbit 2 tournament. It's downloadable for free and great fun in multiplayer. This is not the complete version(misses most of the campaign), but the version most player-made maps will work on. additional maps can be downloaded as well http://www.jazz2online.com/downloads/?page=1 .
They also have Theme Hospital there, but it's only a stupid demo. :/ Anyway: never knew that Jazz had a multiplayer mode?