Ubuntu, as a live USB, when I was trying to troubleshoot an old ThinkStation that I got for free. I didn't really understand what I was doing, and eventually I concluded that something was wrong with the motherboard, that it just couldn't detect any IDE devices.

As for a first experience using a Linux install on a computer, then that would be elementary OS, first in a VM and then as a dual boot with Windows 7 on tank. I got a ThinkPad knowing that it was considered a good Linux machine, though the two main reasons I got that one are that it was quite cheap on eBay and that a laptop with a stylus sounds rad (fuck touchscreens), so I wanted to try Linux. I chose Elementary because it looked like it had more work on its design than other distros and I thought that could motivate me to use Linux. I ended up switching to using it full time rather quickly and removed the Windows 7 partition. I learnt the basics not by following any "intro to linux" tutorials but just by working through various problems, only really learning the things I needed at a particular time for a particular situation.

I started to truly learn Linux when I got into my last year of computer science classes. The first two years were in a very Windows-oriented school, but that last one had 0% Windows. They made us write an HTTP server in Bash and in Perl, I learnt Python by myself, etc., and switched to Xubuntu while I toyed with Arch Linux on my other computers. Now I just feel like I can't get anything done on Windows because I got far more control on my computer thanks to Linux systems, but I cannot say that anyone should switch to Linux because the desktop experience keeps on getting worse; the huge fragmentation means nothing is ever consistent and understandable by normal people.