Extract from WhatIs.com which will amuse da mouse:

A FlashMob supercomputer is a group of computer enthusiasts who gather together in one physical location for a brief time period in order to function as a supercomputer and work on a single problem. Modeled after the flash mob fad that was popular during the summer of 2003, FlashMob supercomputing involves gathering together interested participants who are willing to bring their laptops and PCs to a pre-determined location.

The first FlashMob supercomputing event will be held on April 3, 2004 at the University of San Francisco and is being organized by graduate student John Witchel. As participants arrive, they will be given a FlashMob I CD-ROM; the program boots up and runs from the CD-ROM as a security precaution. The goal of the first FlashMob supercomputing event is to see whether or not an ad hoc network of combined computing power can join the elite group of the 500 most powerful supercomputers. A secondary goal is to demonstrate the viability of supercomputing outside a supercomputer center setting.