This has happened to me at least on one occasion and it’s a common problem, after all an ipod is a mini computer and computer do lock up from time to time!
Symptoms
The bloody things doesn’t respond to your nubs or you plugging it into a computer.
Solution
If you’re lucky a simple hard reset is all that is needed. How:
1) Toggle the Hold switch on and off. (Slide it to Hold, then turn it off again.) It’s the little switch on top on your ipod.