Like making your own song out of a fairly big chunk of someone elses/basing it on someone else's riff. I know people sample and that all the time but rock type bands don't do it that much

Devo - Penetration In The Centrefold
http://www.youtube.com/watch?v=RzPZTYqSCwM

TODD - Black Skull
http://www.southern.com/southern/band/TODDD/sounds/28127-04-Black_Skull.mp3
^at least two different bits that are nicked from it

ESG - UFO
http://www.youtube.com/watch?v=X_vuSse9sFY
Liars - Big long title with 'ESG' in it
http://www.youtube.com/watch?v=X_vuSse9sFY

Anyone have any more fun examples while me tea is cooking?

Not the Kid Rock one let's not talk about that one or should we