I'd definitely consider Myst as one of the pivotal games of this movement. Despite Myst having 'gameplay', it did class environmental storytelling and atmosphere over it, and indirectly created a swarm of likeminded clones. Most have been thankfully forgotten, but there are a few that really embody the whole idea of notgames. They were so weird, even William Gibson ended up using them in his 1996 novel Idoru:
"He didn't answer, watching as his view reversed. To be maneuvered down a central hallway, where a tall oval mirror showed no reflection as he passed. He thought of CD-ROMs he'd explored in the orphanage: haunted castles, monstrously infested spacecraft abandoned in orbit. . , . Click here. Click there. And somehow he'd always felt that he never found the central marvel, the thing that would have made the hunt worthwhile. Because it wasn't there, he'd finally decided; it never quite was, and so he'd lost interest in those games."
Peter Gabriel's EVE: Seems like Peter Gabriel used his pop culture status to band together a ton of disparate artists, to create a 'Interactive Multimedia' game. Sounds like a nineties term for a notgame!
http://easternmind.tumblr.com/post/5419255453/cometalktomeWelcome to the Future: This one is so obscure that there isn't even a gameplay video on youtube, just the intro. I tried to at least make a recording so it wouldn't be totally forgotten, but video recording tools seem to fail to see through the layers of emulation I needed to run it. A few screenshots and info here:
http://www.mrbillsadventureland.com/reviews/u-v-w/wttfutureR/wttfutureR.htm. Mostly noted for having an option to make all the gameplay optional.
Eastern Mind: Probebly the weirdest of the lot, and rumoured to be in development pre Myst. By the same guy as LSD: Dream Emulator.
http://www.youtube.com/watch?v=Ks2PwtTGyig&feature=related