Has she tried any of the Myst games? I think there are five of them, and the last I heard they were working on another. As far as I know those are the last of that type of game.
Initially, I thought you meant puzzle games like the ones at popcap.com. Those are freakin' addicting! It seems like every spare minute I get I'm over there playing Zuma or Big Money.
Oh, and I always loved the 7th Guest. All except for that damn Othello-type game. That was freaking hard. But I just loved the whole atmosphere of it all, and I can still hear that main theme in my head. I have to find that VHS tape I have of the making of the game. I don't know where I got that or where it went to...
*edit*
Oh, I forgot! I've heard very good things about
Syberia and its
sequel. The second one in particular seems to be a visually pleasant game.