I am surrounded by the people who are clueless how fun computer games are and categorically refuse to even try.
Don't. Just don't.
While the article about some teacher telling students to play Fallout 1 as homework and then give feedback about it warms my heart (especially since many of the students grew to love it after all, even if they were non-gamers), or how a middle-aged friend of a friend decided to try out Baldur's Gate 2 he got for free from some fair and finished the game, loving every minute of it: trying to tell people to try out something about which they have negative feelings probably won't work. A bit like telling someone to try drugs or alcohol, or watch pr0n movies.
I've got some non-gamers to try games, but usually the initial interest came from them. It is a bigger hurdle to try out a game than watching a movie or reading a book, because games you need to learn to play. You don't need to learn to read a book (hopefully!) or watch a movie, you can do it passively.
It must feel about the same when I visit my friends or relatives and someone tries to get me to play some Kinect or Wii party game together with them, or some generic console sports or arcade racing game. Ok I try them, but I just can't get over the dislike. I've even played Singstar on PS2 together with friends, but it was overall quite meh. Or yesterday I was in my brother's son's 10 year old birthday party, and I played Wii Sports Resort with the kid. I didn't get much excitement from it, I did it just to please him.
I presume many non-gamers feel the same when you lure them to try some PC game which they don't even comprehend at first, e.g. the controls, the mechanism of the game etc. Oh yeah, I recall when I let my ex try Starcraft (as I had been praising it to her), she just couldn't understand what she was supposed to control in the game, and what the whole game even meant. "Where am I on the screen?".
However, now it occurred to me though that sometimes it may be enough they are watching you play, as long as you explain some things. That's what my gf many times does (she definitely liked to watch me play e.g. Far Cry), but games with grinding or doing some other repetitive stuff, or waiting (Dungeon Keeper! The ultimate waiting game!) doesn't work that well. Those games look even more boring than they are to play. :)