TO BAKE IT: Pierce the whole shell several times with a large fork or skewer and place in baking dish. Cook squash in preheated 375° oven approximately 1 hour or until flesh is tender.
TO BOIL IT: Heat a pot of water large enough to hold the whole squash. When the water is boiling, drop in the squash and cook for 20 to 30 minutes, depending on its size. When a fork goes easily into the flesh, the squash is done.
TO MICROWAVE IT: Cut squash in half lengthwise; remove seeds. Place squash cut sides up in a microwave dish with 1/4 cup water. Cover with plastic wrap and cook on high for 10 to 12 minutes, depending on size of squash. Add more cooking time if necessary. Let stand covered, for 5 minutes. With fork "comb" out the strands.
TO SLOW COOK IT: Choose a smaller spaghetti squash (unless you have an extra large slow cooker) so that it will fit. Add 2 cups of water to slow cooker. Pierce the whole shell several times with a large fork or skewer, add to Crock Pot, cover and cook on low for 8 to 9 hours.
Once the squash is cooked, let it cool for 10 to 20 minutes so it will be easier to handle, before cutting in half (if it wasn't already) and removing the seeds. Pull a fork lengthwise through the flesh to separate it into long strands.