In a large pot cook penne pasta in boiling salted water until al dente. Drain the pasta, leaving it slightly wet.
While pasta is cooking, wash the bell peppers and cut them into 1/4 inch strips. In a large skillet over medium heat place 2 tablespoons of olive oil and saute the pepper until soft. Do not allow peppers to brown.
To the skillet, add the sliced zucchini and yellow squash and saute for 2 minutes. Add chopped mushrooms and minced garlic and saute an additional 2 minutes, stirring frequently. Add the chopped tomatoes and remove from heat.
Dish pasta portions onto warmed plated. Add sauce to top. Sprinkle with salt and pepper to taste.
