Syndarr said:
Albert is a fishmonger. He is 38 years old, 6 feet and 2 inches tall, and wears size 13 shoes. What does Albert weigh?
Fish.
OT: This is the most hilarious joke I know - it's not quite a riddle like the other jokes, but almost nobody gets it.
(I learned this from my cousin, original source is probably someone else.)
Two penguins are walking along the road together. Suddenly a giant doughnut comes rolling down the hill, passes the penguins and keeps rolling out of sight. The penguin on the left turns to the penguin on the right and says "Huh. It must be Tuesday."