Isis
Vote to bring this game to GOG and help preserve it.5
(At time of writing, there is no image or description of the game. I'm assuming that it's the game that I'm thinking of! ^^; )
Isis is a strange game, in a way that I like: a first-person puzzler in the vein of Myst; an exploration within a hollow pyramid; a mission to re-launch a ship carrying the Music of the Spheres; and a vehicle for the band Earth, Wind & Fire. (Yes, really.) And all that making for, I feel, a slightly surreal experience.
It's been long enough that I remember it vaguely--but I do remember it fondly. And hey! Earth, Wind & Fire made some good music! ^_^