There have been a lot of great suggestions - any music, as long as its REAL and you can't go wrong. I must contribute...

Steve Reich is the trippiest shit I've heard to date (check out the 13 minute mind-bender, "come out").

A not-too distant second is probably Boards of Canada (music has the right to children album).
Also love the peaceful freakiness of Animal Collective (sung tongs.)

Obviously everyone thinks their own tastes are supreme, but give any of this a try - you won't be disappointed. (just don't be in a hurry to listen to Reich).