Image by Flickr user peasapImage by 20090608-pirates.jpg
Here's more about the event from their site:
Ahoy Maties! Sign the pirate code of conduct and join the crew. Come face to face with pirates as you search for buried treasure through the Charleston Museum. Every month The Charleston Museum offers a special Saturday program dedicated to providing an educational as well as exciting experience for the whole family. Join us each month for a different themed event including presentations and craft projects for children of all ages.
The event is open to everyone, but if you aren't a museum member then the admission price is $10 for adults and $5 for children.