Scare The CRAP Out of ANYBODY! (kids are best!!!)
Tell a scary story, made by you, to a victim, or someplace where you are sure that your victim will hear. You must be sure to make the story relate to something around you, such as your city, house, school, work, etc. Do this at night, so the story is fresh on the victim's mind when they go to bed. After you told the story, go to your computer or recorder, and create a recording or a scene recreating the story or myth. You must have availability to your victim's room. When your victim is asleep, here's when you come in.
You must have a place where you want to hide your computer or recorder, so your victim cannot see where the sound is coming from. Make sure that it's loud enough to wake up your victim. You could include an alarm sound at the beginning, so you have higher probability that your victim will become wide awake, fast. You then want to shove a handkerchief into your mouth, because you will not contain your laughter when your victim starts freaking out. You have to wait a while after your victim gets a held of him/herself, before you sneak back out, because they probably will not be able to sleep.
You could do it for several nights, and expect the victim to be so freaked out, that they will eventually stop sleeping.
I did that to my young brother and he got SOO scared!! Too bad my grandma jumped in!! -.-