This was my first answer as well. Don't have kids, so I can't brag about how well I raised them...
Second on the list is law school. I actually had no idea what to expect and going to a school in NYC sorta concerned me, as I'd heard a lot about how cutthroat law school and NYC can be. While I was good at taking standardized tests before then, I was always a middle of the pack student in high school as well as college. I was just bored with both, but something about the intellectual challenge of the socratic method and being in an environment that was supposed to scare me lit a fuse. I ended up first in my class after the first semester and graduated magna cum laude with a bunch of other achievements (law review editor, etc.) To this day, I have nightmares about getting up on stage to get my degree and hearing them read my name without the honors. Whatever else happens in my life, I'll know that I rose to that challenge.
Prolly third on the list happened earlier this year. I've done quite a bit of legal writing in the past few years and I was at a conference overseas on the topics I write about. Having professors, government officials and other practitioners come up to me unsolicited and talk about how much they liked my work was pretty shocking. I'm usually very much a wallflower, but I was being lauded by people I really respect and that was very cool (and unforgettable).
