Generic name is flunitrazepam, it's a benzodiazipene type hypnotic tranquilizer. Yes, they are terrible things when misused in various ways, but speaking from personal experience they are extremely useful when used for their intended purpose. It has the effect of inducing very deep and restful sleep fairly quickly, even under difficult circumstances like insomnia, over-intake of stimulants, jetlag, etc. Where I come from they are often called "asshole pills".