Make your own disco
In Episode VI, Chapter Two you come across this genius puzzle. Lift the huge microphone up to the ceiling and then rebuild the brown speakers. You'll find out why soon...
You'll have noticed the blue circles on the floor by now. Two at a time, these spots will light up. Stand on one and your buddy will stand on the other until they're all lit.
Once you've stepped on all the circles, the floor lights up. As soon as this happens, a rock version of the infamous Imperial March will roar into action and the door will open.
A couple of head-banging Gamorrean guards run in and rock out, strumming their axes like guitars. Laugh at their dancing for a while. Then blast them to bits.