Fruit is so versatile: You can eat it straight from the store, eat it later, eat it baked in a pie or muffin, or not eat it at all—just let it rot away and feel guilty about wasting food (the fruit flies will console you). You can also use it to make your own Resistor Jeltone: an edible, functional toy piano.
Created by the Brooklyn-based hacker collective NYC Resistor, the Jeltone won the creativity award at this summer's prestigious Jell-O Mold Competition and has been demonstrated at music festivals. (Probably not the same model, though.) It makes a great holiday gift: After the recipient gets bored or realizes they have no musical talent, they can eat their Jeltone and meet some of their daily dietary requirements. For some people that's enough.