So, and don't ask me how I know this, but if you trip over the power cord for your power strip that powers your entire set up including your router, and you forcibly lose wifi, when you get it back, the home button send you to a 404 page.
This one, in fact:
http://imgur.com/UTw3toV.jpg
Just thought I'd point that out and let anyone know who might have that happen to them that clearing your cache will fix it. I...uh...asked a friend who had it happen to them. Yeah, that's right.