Did you know that you can charge some ipod models up while still listening to them? Very useful for listening at work, where you might not be able to install itunes and sometimes they get locked up while trying to talk to the computer.
Get the USB lead and plug one end into the ipod as normal. Slowly push the other into the USB socket of the computer until you see the ipod start charging up on its display (the pins that supply power are longer). Hooray!
I've heard you can't do it on the newer ones though.