I haven't really learned anything more about science or math, but I love the a Capella arrangements. I also think Tim Blais is a totally hot geek. (show me that "ooh" vowel again, Tim...)
One more video... Tim Blais has pitch-shifted Idina Menzel and Kristen Cheoweth's Defying Gravity. As he puts it: "I just wanted to point out how awesome Idina Menzel sounds as a dude."