Petals Around the Rose is an interesting brain teaser. Here is a copy of the game description:
The name of the game is Petals Around the Rose. The name of the game is important. The computer will roll five dice and ask you to guess the score for the roll. The score will always be zero or an even number. Your mission is to work out how the computer calculates the score and become a Potentate of the Rose.
Simple and challenging.