That's the Gomboc, featured in the NYT Mag's Year In Ideas issue here. It has no internal "weeble" balancer. It just rights itself after a while. The design came out of math, but it also turned out like something quite familiar: the tortoise. Riveting Hungarian video here. (Hat tip: Kottke.)
This article available online at:
http://www.theatlantic.com/daily-dish/archive/2007/12/automatically-self-righting/222709/
