The Lepidoptera Project is a game engine (Graphics, Audio, Input, Networking, AI, Physics, etc...) written entirely in C# and created by me. A small group of people (actually just me since I'm the only one working on the project =/), have begun porting Bullet to C#. Most of the back end is actually complete, including most of the port of bullet (v2.74), but was written in a quick and dirty test fashion to see if it was even possible to create a game engine in managed code. This code is currently being cleaned up and documented before being uploaded. Graphics will be finished first, and the bullet port will be finished soon after that.
This post will be updated to reflect any major changes or announcements dealing with the Bullet Physics portion of the source code.