The NovaDrone from Casper Electronics is an open source, analog experimental sound a light synth. It's currently available as a pre-assembled board, PCB only, or PCB and kit in both single and double versions. Prices start at around $100 for the full kit, with a board only and a parts also available.
Here's the blurb
The NovaDrone offers 3 channels of sound and light.
Each channel has the following features: ADJUSTABLE CONTROLS -volume -TONE pitch coarse tune 24Hz to 750Hz -TONE pitch fine tune -LFO rate .008 Hz (around 1 cycle every 2 minutes) to 750Hz SWITCHES -sync 1 -sync 2 INPUTS - ext sync 3 -PITCH modulation -LFO rate modulation OUTPUTS -TONE square wave -TONE triangle wave -LFO square wave -LFO triangle wave -PWM square wave -High current LED out for off board LEDs.