Cool Open Source Games you should contribute to

Several games I hadn't heard of before are in this list, some rather interesting.

However, it is a bit disheartening to see so many games that are ported engines for old commercial games, or improved clones of the same, rather than new, creative ideas. I suppose it's easier to build a game that's "like SimCity, but better" than to design and create something completely new.

Just in case someone is interested, here's the reddit post on this:

http://www.reddit.com/r/programming/comments/it8ax/cool_open...

A lot more debate has taken place there.

tl;dr: Doom clones, RTS' and games with penguins in them.

Too bad this game wasn't mentioned, it has cute graphics, interesting gameplay, and no penguins: http://joyridelabs.de/game/