S.M.
What's a pirate party without buried treasure? Write up a bunch of clues the day before and give the first one to your son at the party. If your son is younger, make the clues obvious like "Clue number 1: Look outside around your kiddie pool." If he's older make the clues harder, "You will have a splashing good time finding clue number 2." (You get the idea). Then, put clue number 2 by the kiddie pool which would have the next clue written on it. After 10 or so clues, have a buried treasure some where (or even one hidden in a tree). Just make sure the buried treasure has enough stuff in it for everyone at the party. Party Supply stores have cool pirate booty like compasses, telescopes, and gold rings. Good luck and have fun!!!