What was the one video game that turned you into a gamer? brought you to the darkside? caught your interest? lit the fire for your video game addiction even?

I had always liked and enjoyed video games for as long as I can remember.
I know that the first video game I ever played was on an Atari2600 it was also my first home console and the first Arcade game I ever played was Ms.Pacman when I was very young.
I guess I have had a natural progression from the Atari to Nes to the 16-bit systems and so on.

The ONE game that turned me into a full fledged gamer was The Legend of Zelda on NES I remember playing through this game over and over on summer vacation waaay back in the day for over 3 months sure there was the local swimming pool and bike riding with friends and even a small (crappy) local arcade to hang out at for the summer but I remember my mind was constantly on that new shiny gold cartridge that was waiting for me in my first NES back at home,
It was an obsession really I had maps for the whole game even the second quest from the old Nintendo fan club magazine I read all the strategies for it in the then very few video game magazines at the time.
It was different back then before the internet before you found out that someone esle had already beaten the game 50 times before you had even finished it once x_x
yeah THE LEGEND OF ZELDA turned me into a full fledlged gaming geek