What's this?

OK, so Alex came home with this today...  At first look, I'm thinking belated birthday gift from a classmate?   Well, came to find out that the beautiful box was a birthday invitation!  A little wooden box, personalized with his calligraphied name and a little pirate glued on top. 
Delicately open it and inside there is a treasure: gold chocolate coins and nestled among those a delicately rolled piece of parchment with the details for the birthday...

Ahoy Matey
Come sail the ocean blue
Hunt for treasure
And be part of our pirate crew!

So, party is on Thursday afternoon, starting at 5:00!