There are a bunch of grrreat (couldn't resist!) ideas dealing with pirate crafts. The kids will be making their treasure chests first, and if they'd like they can make a spyglass. They then can bring their treasure chests over to a table that will be set up with beads and jewels that they can take and place in their treasure chests. They'll be able to take these home with them. I have a few eye patches, so if there are enough then each child can also have an eye patch. I also put together a "pirate code" book that has information on the crew members of a pirate ship, the parts of a ship, and a pirate dictionary so they can talk like a pirate! (Spoonful.com has The Code craft and template).
DLTK's Crafts for Kids has a great printable and instructions for the treasure chest. Youth Online has another similar template. If you want to get really detailed and crafty, Ashlee's Art has another treasure chest example. And a really cute one featuring a Raven can be found at Ammey's Art Attic.
For more Arrrty craft ideas, make sure to sail towards these sites:
First Stage - this site has a great handout where we got our pirate dictionary and ship and crew sheets