http://en.wikipedia.org/wiki/M.U.G.E.N
It's basically a highly, customizable 2D fighting game engine that captures the look and feel of capcom and snk series of 2D fighting games. I know there are several open source project devoted to MUGEN, but I want to make one using irrlicht engine.
There are like a zillion characters, stage backgrounds, and sound made for MUGEN by the fan community. It would be awesome to support all of these fan-made stuff in irrMugen. Then extend it to support 3D fighters. Then add in network play and we're golden!
Whopee!!! Now I just need to get started...
Please post comments!