When the enevitability of frisbee pizza deliveries becomes widespread it will give irse to a bold, exciting, new sport.
Officially this will be a sport for the upper class. What with butlers flinghing pizzas out of windows to be riddled with bullets from well-aimed winchester rifles. Of course these
people would not actually be eating pizza (unless it is topped with caviar and lobster). However the real clay pizza shooting would be happening out on the street.
The presence of multiple pizza delivery places would make clay pizza shooting a guerilla sport in urban areas. There are countless ways that this would take place. People might be firing their grappling hooks to try to reel in the precious pizza goodness. Others could be using a modified version of the kittypult to launch dogs to an easy meal. Some may even be attempting to feed themselves using human cannons. And of course there would be the ever present drive-by shootings, in which people drive alongside the airborne Italian food trying to put as many bullets as they can in it.
For the most part, people would just be trying to put a bullet through the centre, all the while imagining the look of surprise on the pizza recipient's face as he/she surveys the large exit wound in their dinner.