(I'm sorry about the grammar etc, hope the content comes through) I was 17, when I first had a "burst" of enlightenment, it was more or less the time I started to think critically for myself, coming from a society that I found to be very narrow minded, I at that point felt an urge to read more, learn more and be better. I heavily started to write about my experience's and yielded a great content from it. I naively adopted the notion that: we are what we sculptures us into, our potential is unrealised and too wide and deep to be generalised. With this mantra I came a long way through school, but came out on top without a narrative and started to lack, not being aware of the fact that I was starting to indulge more and more into biases, and the results of my operations started to decline. Then I felt like on a degree of rationality and "winning" I took some steps back. Then around 1.5 years ago in one of my courses at University I started to study the "perception model" and through trajectory I came across books by Nassim Taleb, Malcom Gladwell and finally Bias and Heurestics by Kahneman and Tversky. And after that I have just been rolling along those lines.
To break up the awkward silence at the start of a recent Overcoming Bias meetup, I asked everyone present to tell their rationalist origin story - a key event or fact that played a role in their first beginning to aspire to rationality. This worked surprisingly well (and I would recommend it for future meetups).
I think I've already told enough of my own origin story on Overcoming Bias: how I was digging in my parents' yard as a kid and found a tarnished silver amulet inscribed with Bayes's Theorem, and how I wore it to bed that night and dreamed of a woman in white, holding an ancient leather-bound book called Judgment Under Uncertainty: Heuristics and Biases (eds. D. Kahneman, P. Slovic, and A. Tversky, 1982)... but there's no need to go into that again.
So, seriously... how did you originally go down that road?
Added: For some odd reason, many of the commenters here seem to have had a single experience in common - namely, at some point, encountering Overcoming Bias... But I'm especially interested in what it takes to get the transition started - crossing the first divide. This would be very valuable knowledge if it can be generalized. If that did happen at OB, please try to specify what was the crucial "Aha!" insight (down to the specific post if possible).