Update 1.08 for The Dark Mod -- a fan project that remakes the original in the Doom 3 engine -- is now out and brings with it a massive changelog. Among the highlights are "richer" audio, AI improvements, improved performance, improved textures, and revamped training and demo missions. Naturally, you can find a variety of bug fixes as well.
If you have a working copy of Doom 3 (not the recently released Doom 3 BFG), hit the source to download and play away. The Doom 3 source code will hit soon enough, at which point a standalone version of The Dark Mod should be available.