Half an hour, 21 5-6 year olds dressed as pirates - ideas please!

[MrsFogi]

I have half an hour from dd's party start time and the beginning of the entertainment can anyone suggest what I can do to keep everyone amused as everyone arrives until the entertainment begins? All of them are 5-6 year olds and will be "pirates" but it doesn't necessarily have to be pirate themed.

Feed them?

Or a game like pass the parcel, pin the eye patch on the pirate (blind folded), get them doing a pirate themed craft/can double up as present to take home.

Singing sea shanties?
Yellow Moon generally good for craft activities.

Don't suppose you cuold get them to swab the decks afterwards instead