ezQuake Or nQuake

ezQuake is just a remake of the Quake 1 engine using mouse look. And it is open source and they have retextuting projects.

http://ezquake.sourceforge.net/download/

Or, there is nQuake or QuakeWorld which has the same basic features.

http://nquake.sourceforge.net/

I think nQuake is trying to be a polished version of this game, but could be better if the game where not that fast and with effects changed a bit.