Check out this funny webpage that lists 40 things that only happen in movies. Among the rules listed:
#13. If staying in a haunted house, women should investigate any strange noises wearing their most revealing underwear.
#39. All teen house parties have one of every stereotypical subculture present (even people who aren't liked and would never get invited to parties).
#18. If a microphone is turned on it will immediately feedback
#35. During all police investigations it will be necessary to visit a strip club at least once.