I'd definitely want to see stuff that just interacts on its own, like the aquarium JW mentioned! Weird creatures in a space aquarium trying to form tribes or something hahah
Is it a screensaver if it supports any controls? There are no restrictions but maybe "no input control" would make sense.
AfterDark had a spaceship game at one point - I think a game that "plays" by itself when idle is a good idea
