Wash and prepare all vegetables. Peel squash and cut in half lengthwise. Scoop out seeds with a spoon and discard. Cut squash into 1" cubes. Dice onion, tomatoes, and bell peppers. Cut garlic cloves in half. Place all vegetables in crockpot.
Pour red wine, vegetable broth, and olive oil in a small bowl. Whisk together. Add salt, oregano, rosemary, pepper, and crushed red pepper flakes. Mix together and pour over vegetables.
Cover vegetables with lid and cook on high for 4 hours or low for 8 hours until vegetables are tender.
In two batches puree the vegetables and liquid to desired consistency in a blender or food processor. Thin sauce if needed with additional vegetable broth or water. Season with additional salt and pepper to taste.
Serve over pasta, as a base for vegetable or meat spaghetti sauce, in lasagna, over rice, or as a dip. Turn into soup by adding 1 cup of half and half and pureeing until smooth.