In college we developed a master prank call idea. Here are the steps:
1) Call Dominos Pizza in city A.
2) Place a long, complex order and tell the attendant that the order is for your brother and that you are gonna put him on the phone and to read the order back so brother can "make sure you got the order right"
3) Instead of "getting the brother on the phone", switch to line 2 and call a Dominos in city B.
4) Tell dominos B that you are going to put your sister on the line to make an order.
5) Merge the lines (Dominos A will order from Dominos B), hit mute, and enjoy the ride.
The end result of John's mischief is a spontaneous Abbott & Costello routine, a veritable hall of mirrors of ordering confusion. Be sure to listen for John's evil cackling in the background. THAT'S GREAT DICKISHNESS!