Yes, there actually once was a game called Pizza Wars. Published in 1980-something by Family Games, this beauty was little more than a rules book, but that didn't diminish it's play-value. Like games by Cheap Ass Games do today, this gem held hours of entertainment and provided for snacks at the same time
The premise: The pizza you just ordered/made is the game board, the slices the various board sections, and the toppings, when moved with toothpicks, were the playing pieces. Each player chose a particular topping of his of her liking and the game could begin.
Whoever won a section of the board got to eat it as a reward (Much better than just "having won"). So some players got fast victories on early slices (and thus: Hot pizza), while others got more slices later on. It was very much fun to play, and back in the days, when we had time to play regular role-playing game session, a round of Pizza Wars would often follow.
The game worked best with self-made pizza, as one got to spread the toppings evenly, but worked with delivered ones as well. Order as many pizza as you have players.