I LOVE sweet potatoes, and they are very nutritious. My fav way right now to make them is cubed (I peel the skin, usually - which is easier if you pop them in the microwave for a few min. first) and sauteed with butter and olive oil, and sprinkled with sea salt.
I also bake them, either whole, like fries, or chip size - with olive oil as well.
When I just want one quick (like today for snack), I microwave it using the baked potato button, open it like a baked potato, add butter and brown sugar.

My kids love them, too, so we have sweet potatoes a lot. You can add them to pancakes, or make sweet potatoe pie. Or soup! I added small chunks to split pea soup the other day and it added the right amount of yummy sweetness.
Dang, now I'm hungry!