1999...I think. I was a sophomore in Highschool, and a friend of mine had bought a discounted 2nd Ed. starter box with some pre-gen characters. I spent about 6 hours beneath a small town and interfered in the wars between Bugbears and Xvarts as Mitchifer the Cleric...I think I had a Dwarf NPC helping out as well.
When 3.0 came out, we both joined a game which met infrequently (with me reprising my role as a cleric...but with attack magic, which threw our DM for a loop the first session). It eventually tanked out, and I didn't play D&D again until College, where I had a Gnome Druid go up to mid-levels, and a Fighter/Rogue who barely made it to 5th level during a summer game.
My junior year of college (2003), I jumped ship and started playing, and eventually DMing, Monte Cook's Arcana Unearthed/Evolved exclusively. While elements of 3.5 have been worked into my campaigns, AE is and probably will remain the core system I run for the next several years, regardless of what shape 4E takes. Dungeons & Dragons was a gateway product for me, but I have no desire to go back.
Robert "I have time to Homebrew" Ranting