Cook penne pasta according to package directions until al dente, then drain and set aside.
In a large skillet, heat olive oil over medium heat and add garlic and red pepper flakes. Cook for 1 minute.
Stir in the chopped tomatoes, season with salt and pepper, and simmer for 10 minutes.
Toss in the cooked pasta, and heat through for an additional 2-3 minutes.
Serve in bowls and garnish with fresh parsley, if desired.