What a waste of brandy!
One of my favorites is demonstrating dust explosions. Back in 1998 I was even trying to convince some colleagues to build a special device just for that purpose but they were all chicken and I had no money to do it myself (and I still have no money). I envy the Myth Busters though because they built the device I wanted but much bigger and with hundreds of times more fuel. All I wanted was something that made a big flash and bang in a lecture theater, not something to put outside and create industrial-scale explosions.