Programming
I love to program, and am truely lucky to be able to make it a career. Not everyone can say that they like their job, and I'm proud to say that I get to.
My first introduction to programming was probably QBASIC Gorillas. I'm sure I didn't do anything with it, but I certainly remember fiddling with the code for a short period of time. After that, in 8th Grade I did a project for a class in which I "programmed" a few simple games - using some helper software to do so. While it wasn't true programming, it taught me the basics of loops and conditionals in a rudimentary way.
At some point, I think early 1997, I made my first webpage: http://www.angelfire.com/mo/SamTheGreat/. While it unfortunately isn't up anymore, I can still easily remember the URL - seemingly seared into my brain. My first site even had some basic javascript snippet in it! It was about this time that I also began programming my TI-82 graphing calculator (if I recall, my motivation here was to cheat on chemistry tests :) ).
Over time, I built a number of different webpages, each with newer and better technologies (frames, cgi-scripts, server side includes), until I eventually discovered PHP during the summer before my freshman year of college. Between PHP and the Introduction to Programming using C class I had first semester, I had begun what I now consider to be "true" programming.