is this spoilery? i dunno. don't read on if you're worried. from Dark Horizons:

"Buffy (TV): Bleached blond English vamp James Marsters spoke with SFX magazine and was asked about there being further "special" episodes like 'Hush' or 'Once More, With Feeling'. Seems that as far as he knows, there won't yet be a follow-up musical episode, but Joss Whedon is in the middle of writing a new musical (about six songs in) which Marsters says is "Twice as Good". The big revelation though is that we may see an episode next season in which the cast are required to learn to talk backwards, thus allow the film to be reversed part way through the story - sounds like a blending of the dwarf from "Twin Peaks" and the award-winning 'Backwardz' episode of "Red Dwarf". "

btw, that "Twin Peaks" dwarf gave me nightmares, and i only saw one episode of the show.