Poohsticks
a game in which two or more participants each drop a stick simultaneously into a running body of water on the upsteam side of a bridge; the winner is the person who's stick first appears on the other side (or alternately, crosses the pre-established finish line first). The game was first documented in 'The House at Pooh Corner' by A. A. Milne.
For Spencer's birthday, we're going to find a bridge and play Poohsticks!