Linux people probably already use this thing like crazy - https://www.virtualbox.org/ - but it also runs on Windows and Mac.

It's not just for work - it's also very good for trying out all different kinds of flavors of Linux. It's much less hassle than booting directly into a Live CD/DVD, because you still have your original OS usable at all times, and also doesn't make any changes to your system like Wubi does.