My post to a similar question:
Seems to me it would be alternative topics in science. Stuff we aren't really sure about can be disgusted scientifically here (like aliens, ghosts, teleportation, telekenisis, and yes I realize some of those have much more evidence and understanding than others).
This is a good section to have in the science section. Scientists want to encourage people to use logic and proof to come to conclusions, and there are many subjects that can have science applied to them but that are not yet fully explained by it. Unlike other forums where this sort of thing comes up we can explain things here using fact rather than fantasy or the old "that's stupid" "don't be silly" method which is based just as much on faith as saying something is absolutely true without thinking about it.
Truely fanstastical ideas (like pixies I'd imagine) are easily discounted by science (brain size, evolutionary evidence, lack of evidence of existance, wing/body ratio).
Don't make me get out my copy of Contact to lecture you about "science fiction". ;)
Intelligent Design is a good candidate for this section... if it wants to be considered a science (which, let's face it, is the whole point it was... ahem... made up"). We could get into a good discussion about either why it isn't a science in the first place (being faith based and all) or quickly disprove it with science.