Sudoku for your terminal.
Can't code? Can't hack? Can't do anything cool on the command line? This game will give you an excuse to spend some time in the terminal nevertheless.
Be a cool kid, be in the terminal. Play nudoku!
As a bonus you will even learn the basic vi movement commands.
If you run openSUSE just copy the following into your terminal (yes! the terminal, whoohoo.):
zypper ar http://download.opensuse.org/repositories/games/openSUSE_13.2/ games
zypper in nudoku
If you don't, well, go read the readme.