How do I learn Linux

For one who has never touched Linux, how do you learn and how long does it take to become comfortable?

>>11
It IS available for Linux, I used it because asking how do I run Quake 3 is a meme in Slashdot which means everyone's still playing Quake 3 in the absence of other games.

>>13
Wow, you've managed to list a dozen games across a decade! You're getting close to what's released for Win32 in a month!