Flash mob prank idea: Pirates of the Caribbean

While it's still topical, take lots of people to McDonald's (or some other place of queues) and start singing the funeral dirge from the opening scene of At World's End. I'd really love to see that. We could recognise each other by drawing an East India Company "pirate" brand on the backs of our hands.

"Yo, ho, all together, hoist the colours high. Heave, ho, thieves and beggars, never shall we die."

Mokalus of Borg

PS - I'd also love to have the ability to organise flash mobs easily.
PPS - Or at all.