I want to show some of the modifications you can do to any toy to turn it from what might simply be an annoyance to a tool for glitchy, noisy awesomeness. The techniques here are pretty easy--even if you don't have much experience with electronics. All you need is a willingness to make mistakes, to repeatedly pop batteries in and out when you crash the processor and need to reset things, and a desire to make strange sounds. This instructable, and its videos, show two of the simplest modifications that can be done: pitch bending and body contacts. I've deliberately not shown some of the more complicated methods, like triggering samples using a timer circuit, that you can learn once you've got the basics down. Most steps have videos that carefully go through the processes described in the text. I see them as vital tools to help you see how this is down within a real circuit. Difficulty: beginner to immediate Skills needed: basic electronics (know about resistors, power, ground, switches), soldering (although this is an easy-enough project to get or build soldering skills)
http://www.instructables.com/id/Simple-ways-to-circuit-bend-a-toy/