Whee cheap plastic toys!!! :D
Today, we dissasembled battery-powered plastic toy swords. We observed the internal circuits, and noted the components. Inside, there were two batteries, a circuit board, a speaker, a LED, and a button/switch. We did a bit of circuit bending by attaching a potentiometer to the LED, and adujsting resistance. By increasing resistance, we could dim the LED and lower volume. Others, through experimentation, discovered that they could perform a variety of functions, such as separately modifying volume and light.
On a side note, my row has apparently discovered that their battery is self-charging. They have published a post on this.