Did you miss me? ... Tough luck, I'm back! ;-)
Ultimate Stunts 0.7.2 is out with an improved and integrated track editor, a new car, and a few other minor improvements. I like this project, even if it isn't the best or most complete amongst the Free car games out there, it just has a nice vibe about it.
On the topic of car games, The TORCS guys are running a robot championship. If you think you can write a nice racing robot AI and win the prestigious TORCS Endurance World Championship 2007 then sign up and get involved! More details are on the TORCS website.
Whilst checking for [sadly no meaningful] updates to the Combat Simulator Project, I came across Delta3D (although I'm not sure if CSP uses it). There seem to be a few fairly well featured but not-so-well-known open source 3D game engines out there. Somebody brought up Sylphis3D in the FG forums. JCRPG and Air Carrier use jMonkeyEngine. Are there any other good but lesser-known open source 3D engines out there?