Robot that balances on a ball

This robot uses 3 sets of omniwheels to balance on a ball.  Kinda like a 2 axis segway.  It's quite impressive.

http://spectrum.ieee.org/automaton/robotics/robotics-software/042910-a-robot-that-balances-on-a-ball

"Singularity Drive System"

This is a pretty neat video of I guess you could call it a continuously geared wheel drive. Its simple and seems to work really well.

http://spectrum.ieee.org/automaton/robotics/diy/youve-never-seen-a-drive-system-like-this-before