I found this on a blog somewhere, and it's SO weird.

Watch this clip, and try and work out what he's saying. (No, it's nothing as complex as a whole sentence, just a sound)

Then watch it again without looking at it, and try work out what he's saying.

http://www.media.uio.no/personer/arntm/McGurk_medium.mov

Then watch it again, KNOWING what he's saying, and it'll STILL sound like it did first time.

SO weird.