This idea is about gloves that have delicate sensors attached and that will translate the movements of your fingers and hands into music.
A lot of people actually tap along with their fingers when they hear music - now they can actually play music the same way. The synthesizer could emulate all kinds of instruments, but the most obvious use would be percussion: Ten fingers representing ten drums and snares, with the speed and extension of the fingers representing different ways to hit them.
As a special, you could also use the gloves in conductor mode, where you can add you personal touch to an already pre-arranged piece of music: This could either be used to learn the art of conducting, or simply for fun.
Reward: A pair of musical gloves.