littleBits o26 Speaker

I clipped this onto my synth setup and the way it turns electrical signals into actual sound is surprisingly clean for something this small. Running signals from other modules through it gives me a gritty little speaker I didn't know I needed.

The input jack is what sold me — I can plug my phone straight in and the little speaker handles the rest. My kid built a circuit that turns a light sensor into sound and we've been messing with it all weekend.