There are two ways to read that question, I suppose. If it’s one of those nights when discussions on J.S. Mill morph into discussions on Mark Twain; then into discussions on Blaise Pascal, Klein bottles and other non-orientable, two-dimensional differentiable manifolds; and other random Wikipedia surfing – this game may be for you.
That’s right – I know you’ve all been waiting for it – snake in non-Euclidean space. Mac, PC and Linux, tons of levels, totally addictive. I think the levels are a bit large, personally, but I’m not cool enough to be able to mess with the source code (help?). The best, in my humble opinion, is sphere with the wireframe turned off, no stars. Yippee procrastination.