The Canadian Space Agency's Chris Hadfield is not only an astronaut but he's also a passionate guitar player, and if he wants to keep using his instrument, he has to keep his fingernails short and tidy. (This past December, he recorded his original holiday tune, "Jewel in the Night," at the International Space Station, which may have been the first song ever to be recorded in space!)
But clipping nails in zero gravity takes a bit more effort than it does here on Earth. So, Hadfield made this handy, instructional video that demonstrates how the crew of the International Space Station clip their nails in space without their nails floating all over the place. You know, in case you ever find yourself in a similar situation.