1) Lean over them when there asleep and sing a lullaby really loud and out of tune.
2) Every five minutes yell "The aliens are coming!"
3) Choose a specifice piece of cutlery (eg. a fork) and stare accusingly at that item every time you see it.
4) Buy face paints and paint their face when there asleep. Try doing something the person is afriad of. (eg. clown, zombie)
5) Announce that you are actually a secret agent, spying on somone who lives in your house.
6) Call your house number and announce that you are going on strike. If they ask for a reason, hang up. Caution: Make sure you dont get a wrong number!!
7) Put ice cubes in everyone's warm drink.
8) Every time they speak interrupt them with "Curiosity killed the cat."
9) Set alarms on your mobile/cell phone that go off every 10 minutes.