I started playing Wow on Uldum back in the day with no idea that twinking existed. I got into playing battlegrounds on my rogue, and used to always see Pizza Hut cohorts standing around in the battlemaster area. I thought it was clever and funny that they were named Pizza Hut and a few of the players had pizza and pasta themed names. After seeing them stuck at level 19 for weeks without change, I asked one of them why they never leveled (I can't remember who), they told me about twinks and that's what first turned me on to twinking.
I quit a few months after that, and then came back later and learned more about twinking. My first twink was a 29 hunter named Apnea from Deathwing (Nightfall) in the 29 guild iHustle. Then after the exp-off addition, 29s migrated to Skywall (Reckoning) and I was recruited to play a 29 hunter named Blackout in Glass Shooter FTL. The core of that guild's more active players went on to form Knights of Ni where I wound up, and that's where I really got into twinking and met most of the people I know from this particular niche of the game.
From there I got into 39s at the urging of a friend from iHustle (who also played a 39 hunter named Keekers). I then leveled the 29 Apnea to 39 and eventually wound up transferring to play with the guys from DetoX and GSFTL on Lethon (Nightfall) in a guild named Pulse. I also had a 39 rogue named Revival in Protect the Lumber on Doomhammer (Nightfall). I stopped Wow entirely shortly after that.
I came back again, as I can't seem to stay away. 29s and 39s were pretty much dead or on life support at best by that time, and I heard that 19s were quite active and rolled both 19s that I currently have.
tl;dr - my entire twinking history