Naith
A while ago I made part of a 3D shooter - its woefully incomplete, but functional regardless, and has some fairly high level capabilities. Time got the better of me and I moved onto other things, but with the recent release of Panda 1.7.0 decided to release it, as it does contain some fairly sexy code. I am actually now intending to do some further work on it - see if I can create something playable.

Anyway, the Google code project for it may be found at http://code.google.com/p/naith/.

Also, using Pandas new web plugin you may play it in your web browser, by going to http://thaines.com/content/naith/naith.html.