Liquid Nitrogen in the Pool

At Penguicon 4 in 2006, Nifty Guest Howard Tayler took this video of Penguicon co-founder Rob Landley throwing a bowl of liquid nitrogen in the swimming pool, and the resulting billow of fog.

Amazing Oobleck

Cornstarch and water for a strange non-Newtonian solid sometimes called an Oobleck. Watch what happens when it is put on top of a subwoofer!