I'd say right after I graduated high school, or either when I turned 18. I think the main reason for this, was the fact that I didn't get them anymore. Once I turned 18, my parents stopped buying me games, and I didn't have a job at the time either, so I guess I just outgrew them then.
I still play games on occasion now, but not as much as when I was younger, as most just don't appeal to me now, although, I still wouldn't mind me a Nintendo Wii to play since that is fun. lol