My friends dad watched us playing Starcraft almost a decade ago and loved it.
To this day, it is the one and only game he has ever played (SC + SCII beta), and he plays the shit out of it. During his lunch break, after work (if he goes home the wife wont let him play) before work, whenever the hell he can he plays SCII beta.
My parents just say, "Stop wasting your time and read a book" every time they come and visit. (And they have been doing this since I played King's Quest 1 on my dads IBM PS2) Never really made me stop tho, think it just made them feel better.