This is a project I did that involved "circuit bending" kids toys.   Circuit bending is when you take a wire or wires to the back of a PCB board in order to bypass certain parts of the circuit, a.k.a. short circuiting.  The result can produce interesting sounds as well as more (or less) control over the electronic device.

I circuit bent a toy telephone as well as a stuffed Pumba.  I replaced Pumba's speaker with a 1/4" jack so I could plug him into my amp and run him through my effects pedals.  I would have really loved to do this with the phone as well, but I tried and the signal was just too weak.  A couple notable things I was able to do by circuit bending was singling out certain recordings in the phone so I could trigger them with added switches, and getting Pumba's voice to pitch shift down.

Below are some pictures.

The phone.  I replaced the speaker with a 1/4" jack so that now I could switch between either the speaker it came with (the smaller one) or with Pumba's (larger).  All the switches on the side of the phone were added by me.

Here you can see the PCB board.  The green wires are what I added.

Here's Pumba.  I put a blinking LED in his right eye, just for effect, so he looks like some cyberhog.

Pumba plugged in.  The arrow point to the switch that pitch shifts his voice down.

The whole setup.  Effects I used included chorus, reverb, delay, tremolo, phase, and a wah pedal.