Space walking astronaut. Source
Two days ago, on the 16th, a nightmare became reality. Two astronauts, Luca Parmitano and Chris Cassidy, were going on a routine maintenance spacewalk on the International Space Station when disaster struck. A leak appeared in Parmitano's helmet. At first, ground control thought that it was just a leak from his water bag and that it would quickly stop. After a few minutes, however, it became apparent that the leak was much more serious. Once the water had saturated his hair and gotten into his eyes, ground control finally ordered an end to the space walk. Once the astronauts were safely inside, it became apparent that Parmitano's radio wasn't working because he couldn't hear ground control's messages. The other astronauts on the ISS assure us that he's okay, however.
It seems likely that the leak came from the cooling system in Parmitano's space suit. Adding just another danger on the list of things that can kill you in space.
For more information, check out this article.