So over Easter, my nephew turns me on to this guy:
http://www.stickam.com/ownagepranksI listened to most of his calls and they are pretty good, but apparently, he streams a show live and that's when to catch some of the really good calls.
Also, He'll take requests and prank somebody for you. My nephew had him call his room mate, his mother and a couple others. I think it might be worth giving his live stream a listen.!
CM