Deep Sleep

A group of researchers at the University of Washington have discovered a method for chemically inducing a state of suspended animation, or hibernation, in mammals.

However, there is an unfortunate (if relatively harmless) side effect, as the process involves injecting hydrogen sulfide into the air--about 80 ppm to induce torpor in mice. While the mice may not mind, most humans aren't terribly fond of the smell; it's most commonly produced by rotten eggs.