Yes, but you're not actually watching television, and the difference lies therein the actual participation of the player.
Anyone who think a "mindless game" is really mindless is only fooling themselves. The very act of letting go from reality for a given time relies on the intention of actually doing such.
I can play many games in a mindless manner. Once you play a simple repetative game enough you don't have to even think about it... I'd say that's mindless.
Are you telling me that driving a car isn't mindless because it "relies on the intention of actually doing such"?... because that can be said about anything.
The act of driving a car becomes sub-concious once you do it enough (assuming you're on familiar ground, and often when you're not). The same can be said about playing games. I can play many games while carrying on a convorsation with some one and not miss a beat in game... I'd call that mindless (the online FPS's I play come to mind, along with most rythem games I play).
There are very few gaming genre's that aren't mindless, if you ask me.
Calling a game mindless isn't always an insult. I for one enjoy "mindless" games. They are a nice way to relax. (Of course a good thinker is nice every once in a while too).