netPanzer development seems to have resumed. "New" developer Krom Xp issued an update back in April that I'd not seen until now. He seems to have focused on making the game more stable, which is a Good Thing (tm). This action-strategy war game (doesn't action-strategy sound better than RTS?) is available for Windows and Linux and looks rather cool too - helped by formerly being a commercial game.
The other day I was whining about the lack of single player open source FPS [or FPS RPG] games... well, d'oh, I forgot Eisenstern. A collaborative fork of Sauerbraten, the design for Eisenstern makes for very interesting reading. It will be one huge map with 5-50 hours worth of gameplay, very few limitations on what the player can do, with most story and quest work being done through the guidance of NPCs - although they can be ignored and you can slaughter everybody if that's what makes you feel good.
That's not the only SP-focused mod appearing for Sauerbraten. Somebody has started on a sci-fi horror mod. It's early days but my gut instinct says we'll see more of this due to the ability to rapidly create content for Sauerbraten and the relative eagerness (and decent looking screenshots) of this fella.
I came across Street Rods 3 yesterday. It seems like it is dead although there is talk in the forums attempting to revive the game. An open source attempt to create a sequel to the Amiga classic Street Rods 2, you buy and modify cars and illegally race them to earn cash. The current incarnation only runs on Windows and development has been abandoned. However there still seems to be enthusiasm amongst the people in the forums, just it's offset by frustration at lack of progress. I get the impression it's all artists and no coders - funny how most projects seem to have either one or the other abundance of the two talents, but rarely both.
Anyway, I hadn't heard of SR3 until today and it's been in development for 6 years. Either they were doing something wrong or the Gods hate them. Time for them to sacrifice a few virgins, I think.