Hi everybody 
I just wanted to show off balancing robot:
http://www.youtube.com/watch?v=N28C_JqVhGU
It uses motors, motor brackets and a motordriver from Pololu:
pololu.com/catalog/product/1443
pololu.com/catalog/product/1084
pololu.com/catalog/product/708
The code can be found at my github: https://github.com/TKJElectronics/BalancingRobot
Check out my blog post: http://blog.tkjelectronics.dk/2012/03/the-balancing-robot/ for more information.
Best Regards
Kristian Lauszus