MaKey MaKey lets you to turn everyday objects interactive objects. If you want to learn to create interactive artworks but want to start without any programming or breadboarding, MaKey MaKey is a good starting point.
Getting started with Makey-Makey http://makeymakey.com/how-to/classic/
Controlling Sound:
Sound Plant - http://soundplant.org/download.htm
How to use Sound Plant video - https://www.youtube.com/watch?v=QdLCQ0mz33M
Elektronica - Free VJ software for PC http://en.softonic.com/s/download-software-elektronika
DJMixer Pro - DJ and VJ mixer http://www.djmixersoft.com/
Examples: MUSICAL DRAWINGS
A MACHINES SKETCHBOOK Philippe Dubost - interactive drawing
MaKey MaKey Music Examples Vol 1 https://www.youtube.com/watch?v=wkPt9MYqDW0
MaKey MaKey Music Examples Vol 2 https://www.youtube.com/watch?v=STHZ2FFKYBs
Drum Kit on Scratch http://scratch.mit.edu/projects/2728243/
Piano on Scratch http://scratch.mit.edu/projects/3197818/
j.viewz playing Teardrop with vegetables http://www.youtube.com/watch?v=xvmTav3SYsc
A Breath of Fresh air https://www.youtube.com/watch?v=SyT2sezLtBQ
Musical drawings with SoundPlant http://www.youtube.com/watch?v=uqPys4opLn8
Making a Button from Sugru http://www.instructables.com/id/Sugru-Air-Gap-Makey-Makey-Buttons/
Using a capacitive touch sensor instead of having to be grounded