Anyone see the channel four thing last night about the three scientists?They had to make/give the impression of a ghost by scientific means.
One of the bits of kit was a big speaker that played the sound of a frequency that humans cant hear but can feel.looked mad as all the windows doors ect were rattling like mad and people were feeling queezy but no actual sound from the equptment.
It crossed my mind that one of those would be good at a party so if the old bill showed up for trouble you could just vibrate thier guts till they all fell ill.Had a picture in my mind of riot cops looking around to see what the hell was going on whilst puking up thier dinners.

http://en.wikipedia.org/wiki/Infrasound