Good idea: have a pool party hosted by Jagermeister in Mexico. Bad Idea: pour liquid nitrogen into the pool. Why, someone might  ask? The answer is, while this will help you obtain a killer white fog effect the reaction of liquid nitrogen and chlorine displaces oxygen in the air and causes asphyxiation. The incident injured 8 people and left one in a coma.

[Source: Ebaumsworld.Com]