Some of the .farbrausch demos like
fr-08: .the .product,
fr-019: poemtoahorse. and more like
fr-036: .zeitmaschine which they don't have on their site anymore but which I got saved on my HD earlier. Be sure to check out .kkrieger.
.theprodukkt
Also I liked a demo by Future Crew called Fishtro which they made somewhere in 1992, because they had all the little lemmings swimming there.