If the fourth of July has taught me anything is that you should stand away from fireworks and that people like explosions. That's why the video below is particularly fascinating. You're looking at what happens to nitrogen triiodide when even the most gentle touch disturbs it. The explosion shoots off a purple plum that I can just look at all day long.
The Royal Institution offers and explanation for what happens:
Nitrogen triiodide is so unstable that even something like a mosquito landing on it can set it off. Three iodine atoms cluster around one side of a nitrogen atom. Being crowded around one end causes something called bond strain as the atoms repel each other in a small space. The result is that the molecule is prone to falling apart, explosively.