Prank calls don't really exist anymore with caller ID and everyone sending unknown numbers to voicemail.
I was listening to a Weird Al song about prank calls and realized you can’t really do them anymore now. Also it was funny that he mentioned dialing 7 digit numbers instead of 10
When I was a kid, we would spell out "dirty words" in people's phone numbers and call saying we were from the "Telephone Number Decency League". We'd say the naughty word thier number could spell and encourage them to call the phone company to ask for a new phone number.
Love it. We used soundboards. The Schwarzenegger one was a blast. You get them paying attention with the lines from kindergarten cop then start going wild on them with lines from predator, etc. My personal favorite was "I hope you left enough room for my fist, because I'm gonna ram it into your stomach!" One memorable woman tried to save Arnold's soul with gospel music. I think she enjoyed the whole thing.