My first and only Halo 2 mod.  It was a reskin/retheme of headlong, making it a post-battle scene (in the timeframe of Halo:ODST), and war-torn with downed pelicans, burnt metal, etc.  I don't want to sound full of myself, but it really was a great mod, and I was extremely proud of the result.  I was working on the final touches (nightvision and some more scenery) when my computer crashed and I lost absolutely everything.  I could have pulled it off my Xbox but that copy had terrible edits that I couldn't revise, and I didn't want the mod to be released like that.
The only thing I have left of it, is a terrible quality video.