When boring people like you and I go on vacation, we might go camping in the woods or something. But not NASA. NASA goes camping on a virtual asteroid. And the worst part is that NASA didn't actually have to take any time off: asteroid camping (among other things) is what it does for a living. Asteroid camping. Not fair.
Since humans have never visited an asteroid (or even deep space) before, and since it seems like it would be kinda fun to go and do that at some point, it's NASA's job to figure out how to make it happen. Getting to an asteroid is just one part of that; the other part is figuring out what to do (and how to do it) once we've made it there, so NASA has set up a mock Multi-Mission Space Exploration Vehicle (MMSEV) in a virtual reality environment and stuck two guys in it for a three-day weekend of asteroid exploration.
The MMSEV is like a little mobile home in space. It has sleeping quarters for two, a little kitchen, a waste collection system, and can carry enough food and water for missions of over two weeks. There's a cockpit in front, and on the back are "suitports" where astronauts can get in an out of space suits to do EVAs. On this simulated mission, an astronaut and a geologist flew the MMSEV around a virtual, spinning asteroid to practice maneuvering, and tried to figure out the best way to use the MMSEV's arm to help someone in a space suit take rock samples.
Lessons learned here will help NASA develop techniques for future space missions, and you can watch the simulation in action in the video below.