I usually freeze my overripe bananas, peeled and wrapped in wax paper or a piece of plastic wrap. That way I have them in the event that I want to make a smoothie. I used 1 1/2 for today's breakfast.
If you have a Champion juicer (I don't know the construction of other types of juicers, so I can't vouch for those varieties), you can make an incredible "banana ice cream" by using the blank filter instead of the strainer filter and the "ice cream" will come out the front of the juicer. I learned this recipe on Kauai, and we started freezing bananas, mangos, pineapples, and all other varieties of fruit to make our own 100% fruit "ice creams".