My ipod won't turn on or connect to itunes?

This morning, I charged my ipod, headed off to school, and it was working fine until I decided to use it again later. It wouldn't turn on at all, I pressed the center and menu button, the center and pause, etc. I've tried everything, I plugged it into my computer. The usb port recognizes something, but itunes doesn't see it. WHADDO I DOOO!!!