From Disney's website:
Name: Disney's Pirate Adventure
Location: Disney's Grand Floridian Resort & Spa
Description: Offers children ages 4-10 a pirate adventure, complete with bandanas, following clues and searching Bay Lake and the Seven Seas Lagoon for buried treasure. Two cast members, including a lifeguard, accompany the group. $24.95 per child, includes PB&J lunch with Gummy Bears, Rice Krispy treats and fruit punch box. Children must be potty trained, no pull-ups. Must cancel 24 hours in advance or pay full price.
Hours: Monday and Thursday 9:30 am - 11:30am, sign up at 9:15am
Information: (407) WDW-DINE (939-3463).
My grandson (7y.o.) did this last summer and really enjoyed it ... the "pirates" followed clues to the Polynesian Resort, the Contemporary Resort and finally found the treasure at River Country.
Although it says $24.95, I think it's closer to $29 now.