Pi is Wrong (youtube.com)

If you, like me, struggled through geometry class more than other math classes, or if you never managed to memorize the relationship between pi and sin/cos/tan, you should watch this. Personally, I think that tau is far more intuitive. If I could go back, I would probably use tau for all my math/physics classes and simply do the conversion tau = 2pi as needed.

Edit: If this interests you check out http://tauday.com for more.