Passive Bicycle Stability:
An ordinary city bicycle is given a push, then coasts without motors or control.
The bicycle is self-stable even when given a large perturbation by the handler.
Above a minimum speed many bicycle geometries result in naturally stable dynamics, as predicted by linear models.
Bicycle dynamics and walking dynamics are similar in that they are both nonholonomic, which can allow for stabilization without dissipation.
You can find more about bicycle dynamics on Andy Ruina's website.
Video by Steve Collins.