This article on NASA's website says that several astronauts have claimed and confirmed something interesting:  Moondust smells and tastes like gun powder.  They noticed it when it was brought into their lunar lander on the boots of their spacesuits.  But moondust and gun powder aren't the same thing.  Gunpowder is made up of nitrocellulose and nitroglycerin.  Moondust is silicon dioxide glass, olivine, and pyroxene, among other things.  Scientists are unsure why it smells the same as gun powder.  (via Boing Boing)