"Butch" Wilmore needed a socket wrench. That's a problem since he's 155 vertical miles from the nearest Ace Hardware.
Wilmore is a Commander on the International Space Station, and when he mentioned to his colleagues on the ground that he needed a wrench, they got to work.
First, they designed it in CAD, then sent the file to NASA where it was transmitted to the ISS. The code was pumped into a 3D printer on the station and after being built layer by layer, Wilmore had his tool.
It didn't take a rocket or months to get there, and that was the goal of Made In Space. The company behind the project designed and built the 3D printer specifically to rapidly prototype parts in a zero G environment, and the wrench was the first tool ever printed on the station. Read how it went down over at Backchannel.