There's a VAST amount of random things people create for Mousehunt, some of which is pretty cool.
Here's the one that started me realizing there was a world of MH beyond the forums. (Hint: Zugs Tower flowchart.)
Here's a site where someone created a website just to track his collections, but by pictures! (Greyed out for not yet found.)
Here's a breakdown of farming GlowingG in the labyrinth, and what trap setup is best.