Some new techniques for a circuit bending newb?

Not being an expert on circuitry, I'd love to know some new circuit bending techniques. After dissecting an old toy keyboard, I found a way to manually change the pitch with a knob and bend the notes bit with metal contacts. Although that was fun, I didn't even come close to any of the crazy sounds I've heard a lot of modified instruments make on youtube.

Can anyone give me suggestions on how I could make my toy keyboard a crazy psychedelic noise machine?