Much like another user posted, when someone says "video game," I think of the last game I played. Unless it's something along the lines of "What is your x game," like favourite game of all time or games that define a genre.
I actually thought PacMan. That was the first thing that popped into my mind, which sort of surprised me. I think PacMan must be a placeholder in my mind for video games as a piece of technology. I associate Mario, Sonic, etc with specific companies and marketing.