If you use Linux at all, you're familiar with the concept of a package manager. It's the program that your system uses to keep track of most everything installed on your system, and allows you to add, remove, and change them around.

But, they can sometimes be used to kill time.

If your operating system is based on Debian, like Ubunto or some such, then your package manager is APT. If your package manager is APT, then you can use a frontend called aptitude to manage your programs installed on your computer.

Nothing too exciting, right? But, if you get bored, you can press CTRL+T to open the menu, where you see the option "Play Minesweeper", so you then press P and get:

You can use the arrow keys to move your cursor around and Enter to test a square for a mine. I don't really know any more of the controls since I am actually pretty bad at Minesweeper...

But, it's good for a short distraction while you're doing boring sysadmin stuff.