Here's a nasty one I learned as a kid.

A medeival kingdom was situated on an island in the sea, with a bridge to the mainland.

The only problem was, any one who tried to cross the bridge would be attacked by giant mystical yellow fingers and dragged to the bottom of the sea. The king had sent his bravest knights to cross the bridge past the fingers, but they just weren't fast enough.

One day, a young page wanted to try crossing to the mainland. Neither the king nor his remaining knights believed he could do it, but before they could argue, he was already halfway across the bridge...and quite surprisingly, the yellow fingers did not rise out of the water to grab him.

The moral of this story is: let your pages do the walking through the yellow fingers.

Adam "I know worse ones than this" Bomb