I always knew Adrian was that right guy for me :-). He was in thought yesterday pondering various ways to prove that [sin(theta)]^2 + [cos(theta)]^2 = 1, and he commented that it would be an extremely straight-forward proof if preceded by a proof of the Pythagorean theorem. I agreed, and then got all excited because I remembered one of the many proofs of the Pythagorean theorem that I learned in college, so I sit down and show him. Then he gives me a refresher of how to integrate with trig substitutions. Which was fun, because my calculus is SO rusty. See, calculus is his favorite kind of math, and geometry is mine, so we get to complement each other. Haha.
Then we ate a dark chocolate orange. Because that's always a good idea.