Did you know that pepperoni is the number one pizza topping choice? That's why I'd bet that it's gonna be your number one calzone filling choice!

Preheat the oven to 450 degree F.
In a medium-sized bowl, combine the pepperoni, mushrooms, cheese, and spaghetti sauce; mix well and set aside.
Divide the dough into 2 balls. On a lightly floured surface, spread each dough ball with your fingertips or the heel of your hand to make a 7- to 8-inch circle. Spread half of the pepperoni mixture onto each dough circle, forming a semicircle of filling on half of each dough and leaving a 1/2-inch border around the edge. Fold the dough over the filling, forming half-moons. With your fingers or a fork, pinch the edges together firmly to seal. Place the calzones on a baking sheet that has been coated with nonstick vegetable spray and brush the top of each with 1 teaspoon oil. Pierce the tops 3 or 4 times with a fork or knife. Bake for 18 to 22 minutes, or until the crust is golden brown. Serve whole or cut as desired.