First, it's free.  But it's also awesome and effective and hypnotic, so when you combine the price with the effect it's great.  However, throw the dev some money as they damn well earned it.

Its free, it's sureal, its a screensaver/background in an abstract ship graveyard.  Nice looking, though the sound is a bit loud.

A free surreal cityscape generator that you turn on and watch the viewpoint shift and change as you wander randomly.  Lovely and simple.