Not an official representitive but Lips of Suna has some graphics tasks and there as open as your going to get
Videos 2
For discussions ther is a forum and irc: lipsofsuna on freenode
The wiki is quite extensive on style and workflow and the data repository is here
Edit: Added stuff
Adrix, you sorta need to make people /want/ to contribute when you're asking them to ;) Put some screenshots, videos, a long, pleading article on why Lips is the best game to contrbute to etc...
Thats your department
Well, there is a lot of good games wich will be good to contribute, :P, but maybe talk more about the project, the general idea, the graphic style you aim :), the quality, if it is 3d, talk about the polycount or technology, if you have some palette, inspiration or whatever you can imagine :)
Did I mention I'm not an official representative?
Anyways heres some videos 2
For discussions ther is a forum and irc: lipsofsuna on freenode
The wiki is quite extensive on style and whatnot and the data repository is here
Adrix: You made the first post, you're the only one who can edit it (other than an admin)