Over at VintageComputing.com, they have a fun feature on 'Trippy Computer Games', checking out some of the odder oddities out there, from the CD-ROM era and before.

One I was rather unaware of was Midway/Time Warner's Endorfun, of which the creator explains: "The music in Endorfun contains subliminal messages designed to help you feel good about yourself and the world around you, to help you enhance your state of well-being and personal abilities. In addition, after every time you play, a positive message appears on the screen to reinforce these thoughts…" I feel better already!

Also mentioned, and something I remember, was Galapagos, which "...starts off with the intriguing supposition that the main character (Mendel, a four-legged spider-like robot) cannot be directly controlled by the player. Rather, the player can only interact with the environment, and allow Mendel to form its own conclusions about cause and effect." Needless to say, hilarity ensued!