Transformers

Find out more about it here.

Rohan

Find out more about it @ TJ's site. Make sure to read the "read me" file.

Shark

Very cool looking rig! Find out more about it here. Works only in Maya 8.5, anything newer and the mesh freaks out.

Blake

Find out more about it here. Lots of info and a video. Rig discussion can be found @ the 11secondclub.