...for some slightly crazy 'modern' Soviet acapella sacred choral music, try Schnittke's Concerto for Choir (the last movement is my favourite).
Anyway, some other composers and performers have definitely dabbled with psychedelics at some point, but I'd rather not give names...
ya know when I first started going to Raves in the Early 90's DJ's almost always intro ed with some kind of classical music that flowed nicely into the world of thundering house music.