Cubemen is now available for Linux in 32bit and 64bit flavours. It’s only currently available on Desura and the Ubuntu Software Centre.
About: Cubemen is a fast paced, action packed, original 3D Tower Defense game that mixes TD and RTS in the most exciting way possible! Get ready for some crazy Cubemen action! Play a purely defense game in various modes on a sweet selection of levels, or go into Skirmish mode and play a new type of TD game against either the computer or another human opponent. That’s right.. Two way REAL-TIME TD against the computer or a real person!
Download: Ubuntu Software Centre | Desura