A dude in Germany has built a costume of General Grievous from Star Wars Episode III: Revenge of the Sith (as well as being featured in numerous other Star Wars works of fiction). Yeah you read that right: a General Grievous getup. And it not only looks incredible but it moves incredible! Check it out!
This guy has a longer video here that has more detail of the costume.
I bet he's gonna get slammed with requests from people to loan Grievous' help on Star Wars fan films :-P