A game involving the classic Easter candy, Marshmallow Peeps. Each Peep has a toothpick sticking out of the front of it, like a lance. Two Peeps, so armed, are placed in a microwave facing each other. As they are heated, they expand, until one Peep's toothpick makes contact with the other, causing the unfortunate bugger to pop.
Peep jousting is one of the few things those nasty lumps of sugar are actually good for.