Lets face it -- π sucks. Not pie, pie is genuinely awesome and so is the fact that "pie" sounds like "π", so we can have fun with things like this. But seriously... π? It's totally off by a factor of 2!
For more on τ day, check out the Tau Manifest at http://tauday.com/ and of course http://halftauday.com/ if you're still a fan of π.