The Chickenizer Infinity Project
Three maps, a physics model, and the point of the whole package, a sounds patch. The maps have nice flow, and support a good range of players. (The texture choices sometimes need a bit of work, but...) The physics model is plainly insane, and massively increases the damage you can do with your weapons. (A film of one of the maps is included, so that you can see for yourself what happens.) The sounds patch, though... wow. Mostly digitized (and seriously modified) voices... it ranges from drop-dead funny to seriously surreal. This package is net only... but your local netgroup will enjoy the changes imposed by the various pieces.
Levels in map "Pfhor Pfheria Park":
Pfhor Pfheria Park 1.0
Levels in map "Phatal Phred & Deadly Morph":
Phatal Phred & Deadly MorPH (V1.7)
Levels in map "Yenoph Derph":
Yenoph Derph (b21)