I hadn't actually heard this one before, but it was on the radio today and it made me laugh aloud. Lizzie wasn't impressed as she first heard it at infants' school - but there you go. I've updated it a little to conform to my own prejudices:
Three members of a rock band are at the top of a magic slide. They've been told that whatever they shout on the way down is what they'll land in and get to keep forever.
The lead singer goes first, launching himself onto the downward slippery slope he yells "Gold!"
He lands in a puddle of pure gold.
Then the guitarist slides at great speed shouting "Silver!" He lands in a pool of pure silver.
Then the drummer jumps onto the slide shouting "Weee..."