Here’s a logic puzzle for you from The Little Black Book of Brain Games.
“A man lives in the penthouse of a skyscraper. Every morning, he rides the elevator down to the ground floor to go to work. On his way home every evening, though, if he’s alone, he can only ride the elevator half the distance up the building and then has to walk the rest of the way up – except if it’s raining! How can this be?