Ben

Find out more about it here.

RC

Find out more about it here. (link is dead, anybody found it somewhere else?)

Kien

Head over here and grab the rig by either tweeting or posting on Facebook about it. The actual site needs registration. Looks to be all free (I haven't signed up yet).

Bonnie

Find out more about it here, including demo and sample clips.

Alex

Find out more about it here. Download it here.

Günter

This is a cool looking rig, just be advised that it's not free (only $30 though). You can get it here and check out the blog here.

Flower

 Find out more about it here.

The External World Rigs

 From David OReilly

"I’ve decided to release all 65 character rigs from my short film The External World as a free download. You can use and modify them in any way you like as long as it’s for a non-commercial purpose. Showreels, short films, indie games, all that stuff is cool - just give credit. If it’s web based - include a link to my site."

There you go, pretty cool!

Head over here for more info and the download link.