Here, I'll start. When I was 8 years old, my parents went to a dinner party and plonked me down in front of the host's computer so I'd stay out of their way. The game they booted up to keep me occupied was Space Quest II. Little did they know what impact that would have on me...
It must have been either a copy of Skipper & Skeeto 4 or Voodoo Kid that we had gotten with the old Compaq my mother bought through work. Later I played Pink Panther: Passport to Peril that we had borrowed from the library.
That said, I didn't become aware of Adventure as a genre until I was 13 and the adult at my after-school computer club put The Curse of Monkey Island on a projector and we all played it together. That was my gateway drug, as soon after I played around with a front-end for DOSBOX to play the first two Monkey Islands and Sam & Max at a LAN party.
Having missed out on the golden age of adventure games helped create the drive that is currently fuelling my preservation efforts at The Royal Danish Library.