lol
If I try a little harder... crud. I used to know just the perfect game to reference. It'd blow your mind. But now I've lost it >:(
Basically it involved hunting aliens in a... I think it was a 4 dimensional space or perhaps a space defined by a Fourier transform. Anyway, either I don't remember the premise well enough to do the right searches or it's dropped off the internet. Certainly the places I immediately think to look for traces of it no longer exist.

Suffice to say that it was a really weird 'game' built by a math professor for some obscure reason. It wasn't entirely 'fun' but it was quite interesting. Basically you wave the mouse around watching how the field changed and used that to intuit where the 'alien ships' were. Once you hovered over it you 'destroyed' it and earned some points. Each round had more ships to find and, I think, a shorter timer.
A fun little game that I found around the same time period is called Survival Crisis Z. It's also a bit off-the-wall, but a little closer to mainstream and actually quite interesting to play. It's decidedly violent and a touch gory though in a typical low-fi zombie apocalypse way.