You may not ever find yourself in the situation with leftover pizza—but maybe you find yourself (lucky!) with a glut of pizza, and after the slice you'll relish for breakfast tomorrow morning, cold from the fridge, you're not really sure what to do with it all.
Make like Karl Rosaen and make a savory bread pudding with your leftover pizza. (Why not?) Dice pizza and any vegetables you like and layer in a dish with an egg-milk custard mixture and Parmesan cheese. Bake until bubbly.