In a small bowl, combine the first seven ingredients. On a lightly floured surface, unroll pizza crust into an 11 in square cut into four squares. Transfer into a greased baking sheet. Spoon spinach mixture over half of each half of each square to within ½ inch of the edges.
For each calzones, fold one corner over filling to the opposite corner, forming a triangle; press the edges with a fork to seal. Cut slits into the top. Combine egg and water, brush over calzones.
Bake at 375º for 12-15 minutes or until golden brown. Serve with spaghetti sauce