The one legged race (t'other got blowed off by some chain shot doncha' know!

I'm told that ring and hook is an authentic pirate game consisting of just a string with a ring and an eyehook. The string (line)is taped to the cieling (overhead in Naval parlance)while the eyehook is placed in the wall with just enough line for a good hand to swing the ring up and onto the hook. For a more piratey look you could use a child play pirate hook. Many a ship's captain has had to swear allegiance to the Republic of the Keys and fly a Florida flag after loosing this one.

I Like a good treasure hunt. Being that these are all older kids you could easily do a road rally treasure hunt. Navigating by compass (e.g. Set sail by the North Star and at (street name which is piratey) come about to # degrees. You can make it hard or easy and ask questions whose answers are shop names, locations, etc. all piratey of course). If you're near a railroad line you could have them count where X marks the spot or leave plastic dubloons at each sign with an X on it (that takes good eyes on the part of the navigator, the skipper of the ship should be watching the sea lanes!) Just make sure you do this before they get a ration of grog.
No drinkin' and sailin says I! Aaaarrrr!