Schwarzschild I

Here you can fly a spaceship around a Schwarzschild black hole (and, if you like, try to catch an orbiting satellite without falling into the horizon), from the point of view of an external observer.

Schwarzschild II

The same thing, but now from the point of view of the infalling spaceship, giving you the chance to cross the horizon. 

2d Ising model

Here you can watch the 2d Ising model struggle towards equilibrium, and you can adjust the temperature by yelling at it through your microphone.