One of the most surprisingly succesfull demos of 2000. Surprising because it is based on a rather simple package:

Randomly generated vector effects (in the beginning) which give a quite eerie feeling to the demo (together with dune's ambient/techstep soundtrack), and an old (but very fast) tunnel/image morphing effect. The rest is all done by the huge work of synchronization between the effect code and the music. Yes, psychedelic is the word.