I recently came across an Indie game called Audiosurf. It's a simple puzzle game kinda like Frogger where you have to make a little car dodge obstacles and score points by hitting coloured objects as it moves across the track, but the main feature of it is that you can choose any song you want from your hard drive and have it play in the background, and the path you're riding on will morph, switch colour and go faster/slower to the rhythm of the song. The game struck me as extremely trippy and psychedelic, because of the wild colours you can see, the way the music gets 'translated'/'converted' into motion, and because it feels like you're sitting there while you're 'chasing' something. It reminds me of the way I feel when I'm tripping. I think this might be a very fun game to play while tripping though I've yet to try it. I'm recommending it though.

Youtube video:
http://uk.youtube.com/watch?v=oOfdccaZnBU&feature=related

You can find the game on bittorrent sites such as www.torrentz.com

different game but has anyone played on the ps1 game LSD ?
http://en.wikipedia.org/wiki/LSD_(video_game)