Katskorner did a post this morning on telephone prank calls. It reminded me of one my friends and I would pull off when I was a kid. It was deliciously funny and we learned a slew of words we had never heard before.
This particular prank had to be done in the early hours of the morning so it could only be done during sleepovers and only when we could get to a phone without out parents knowing.
At about 2:00 in the morning call your target. When they struggle awake and answer the phone say, "Hello, is Roger there?" (Or Bill, Bob, whomever.)
Politely listen to the grumbling and hang up.
Give them a half hour to get settled in and back to sleep, say 2:30. Call and ask for Roger again. Their response should be a little sharper this time. Politely listen to the grumbling and hang up.
Give it a good half hour and do this again at 3:00. Your victim will be a little irate this time but listen and hang up without a word.
Getting back to sleep this time is going to be difficult for them so give them an hour and a half, say 4:30.
At 4:30 you make your last call, different from the rest. When they answer the phone, probably screaming into it by now, follow up with, "Hello, this is Roger. Have there been any calls for me?"
The results should be spectacular. They always were when I was a kid.
Of course now-a-days there is call display which we didn't have. Make sure to turn it off when you try this because even though you are all adults I know you are going to try this.