Excel Bugs and the intricacies in doing arithmetic efficiently and correctly. We normally take all this for granted but there's much more going on behind the scenes (especially in Mathemtica) to ensure correct arithmetic.

Cool 3D projections of 4D polytopes

Probably the only place you'll see a complete K65 graph anytime soon.

click to play

Really nice demo of how something that seems like a bunch of totally unrelated ideas can actually just be versions of one central idea if viewed properly.

Interesting strategy games which you can play against others.

Really interesting twists on mazes

Wow - a respected mathematician believes he has a DISPROOF of the Riemann Hypothesis! I'm surprised I hadn't heard about this earlier. As far as I can see, the jury is still out on this, but it would be a huge shakeup in the mathematical world if this turned out to be correct. Riemann's hypothesis is the basis for lots of other mathematical results and it's truth has been taken as a given for a long time.

Redotted from Mike

Hey Mike - here's what you were asking about. I should have remembered this algorithm. It's pretty much just defined as "what has to be".