It's super-easy to cook spaghetti squash in a slow cooker. If you need it done sooner, you can also cook it in the microwave.
With a sharp knife, stab a few slits in the spaghetti squash. (Be careful, it is hard! If you have a hard time poking a hole or cutting a slit in the squash, you can either microwave it for three minutes to soften the skin just a little or, if you are home during cooking, do the slits halfway through cooking.)
Place whole squash in a large slow cooker and cover. Cook on high for 3-4 hours or on low for 6-8 hours.
Tips: If you are going to be away from home for longer than 8 hours, place the whole insert and squash in the refrigerator the night before – the cooling will buy you an extra hour of time.