Professor McGonagall: Professor Moody! What are you doing?
Professor 'Mad-Eye' Moody: Teaching.
Professor McGonagall: Is... Is that a student?
Professor 'Mad-Eye' Moody: Technically it's a ferret.
Straight after the second task Hermione wraps her own white towel round Harry, but between shots it jumps back to her shoulders, then back to Harry's several times.
There is an actual band in Canada called the Wyrd Sisters who tried to stop the November 18th release of 'Goblet of Fire' in Canada because there is a band of the same name in the movie, but they lost their case.