1. Lightly oil two 14-inch round pizza pans. Unroll crescent rolls and separate dough into triangles. Fit 16 triangles from 2 packages into each pizza pan.
2. Spread half of spaghetti sauce on each pizza. Divide mushrooms and olives evenly over sauce; sprinkle with oregano. Sprinkle cheese over both pizzas.
3. Slice sausages diagonally; arrange in a pattern on the cheese.
4. Bake in hot oven (400°) 20 minutes, or until crusts are golden-brown. Garnish with a sprig of fresh basil or parsley, if you wish.