Here's one I witnessed in an office about 25 years ago. Some engineers filled a plastic 35mm film canister with a bunch of the waste paper from a three-hole punch. That's basically the little white circles of paper. Then they took a can of compressed air and, with the cap mostly on the canister, slowly filled the canister with super-cooled air from the compressed air canister. Then they fully sealed the cap and went to talk to the mark. They placed the canister nearby -- on the mark's desktop computer, I think. Just out of sight. To avoid arousing suspicion, they stayed and talked to him for 30 seconds or so. Then they walked off to go back to work (and watch the prank unfold from a distance).

That little canister sat there for a while, with the super-cooled air slowly warming to room temperature. As you know, the molecules of cold gasses are very close together, and they start to expand outward as they warm. So when this canister got warm enough, there was enough pressure inside to pop the lid off and distribute the little white paper circles in a perfectly random pattern in a circle about six feet around the mark.

It was glorious.