Post your favorite theorem and discuss it a little.
I don't have a favorite theorem necessarily, but here's one of my favorites: http://en.wikipedia.org/wiki/Banach%E2%80%93Tarski_paradox
This is a completely counterintuitive notion of which I have virtually no understanding, but it has that wonderful mysterious and paradoxical quality that can only be achieved by mathematics. Uli, why don't you list one of your favorites?
Does anyone have any idea how the extra credit questions work? Can we turn them in at any time or are certain ones due by a specific date?
My personal favorite are Zeno's paradoxs.http://en.wikipedia.org/wiki/Zeno_paradox. Every one of them seems to be valid mathematically, but all of them defy common sense. The reason for this is that Zeno bases the the assumption that you cannot infinitely divide something. Eventually you get to the smallest unit of time or distance, and then you can't break it down anymore.
