Sauerbraten [more screens]
Cube 2: Sauerbraten Trooper Edition has been released [download]: new logo, new maps, new weapon looks, bots! (from BloodFrontier), movie recording function (I have to check this out ASAP), rag dolls, new music, and so much more.
The bots are rather dumb as of now and don not know what a powerup is yet but they're definitely better than no bots at all. What I found most amazing about this release is the characterization of the player models. Each of the three has a little back story. I felt that Sauerbraten had no soul before this release. Now it has a little soul. :)
The tank simulation engine Mark IV [project, web page, blog] v0.80 Alpha-1 is out and first-time playable over network. It however uses FMOD (which can be avoided, see this) and RakNet. Windows users will be able to use the pre-compiled binary.
A little arcade
Atomic Worm has recently been open sourced. It appears to be a Pacman-Snake mix plus different grid types plus the visual style of Transcend. Source available here. It uses the PopCap Framework, which appears to be free software.
Portable game packages
The Damn Small Nexuiz (DSN) project provides a slim version of Nexuiz with the aim to make it playable on netbooks. Deja Vu?