I have the Explorer title in World of Warcraft. I don't play any more, but that thing required going to every area and doing almost every quest your faction could take. I got it after Cataclysm came out, so there were a lot of areas to cover. It also means I've got a pretty good knowledge base of Alliance lore, since I also liked to read the quest text.
I almost sorta had the world high score in Pepper II for the ColecoVision. I saw the score on the Twin Galaxies website, knew I could beat it, had a party with friends to film it to submit, and contacted the guy who did verification. Between the time I spotted the low high score and filmed my own, he'd been contacted by someone else who had beaten me by a fairly slim margin. I was so distraught I never tried again, but now I'm wondering if I should.
I'm sure I'll think of more, but these two came to mind pretty quickly.