There are many uses for bananas, including the peels. For instance, you can dry out banana peels, grind them up, and use as a potassium and phosphorus rich mulch for new plants and seedlings.
You can skip the grinder and cut up banana peels and chuck them in the soil as plant food. This is especially effective for roses and staghorns. It also keeps aphids away from the roses, although I don't know why.
Put a banana peel into a large jar, cover it with water, and let it soak. Top up your watering can with the banana peel liquid of one part banana-peel water to five parts regular water. Makes great liquid fertilizer.
The tryptophan in bananas can be a relaxing mood enhancer, helping to combat the symptoms of depression. That is also why bananas and chocolate are so good to set the mood.
Adding a peeled banana in with a roast will tenderize it. You can also put a banana skin on top of chicken pieces to keep them moist while cooking and it does not affect the flavor.
One of my favorites is to use a cut up banana on cereal to eliminate the need for sugar.