In order to know the funniest prank I have ever pulled, you'd have to know a good amount about me, about the friend I pulled it on, about what we do, our inside jokes, our history, etc. etc.
That will take too long and chances are it wouldn't be funny to just your average Joe Shmoe because they wouldn't understand the above.
You're unable to send 15+ years of information to another persons brain instantaneously and then have them understand ever single one of your opinions, views, morals, and all that good stuff so it's not happening anytime soon.