Norwegian engineer Kåre Halvorsen has developed the MorpHex hexapod robot sphere prototype that reminds us somewhat of a Metroid morph ball mixed with the design ethic of a Portal turret.
The robot has six retracting legs that allow for dancing and some rather fluid, sort of artistic movement that reminds you of the swelling and fading waves of a stock screensaver on your computer. However, as the spherical shape would initially have you presuming, it doesn't roll yet. The technology and programming implemented into it haven't been able to accomplish this yet; but Halvorsen was wise in quickly saying this was next. Check out his pretty fascinating achievement in the video below.