How many times have you found just a single resistor to bend?
For instance, this Buddha Machine is a one-stupid-resistor-toy:
But this time I connected a pitch knob and a LDR in series.LDR is in front of a flashing led drived by a 555 timer. The result is an interesting pitch-tremolo-like effect:
This is the schematic of the added circuit:
I used a fixed value (1k) for R1, but if you put a variable resistor you can change the amount of dark time besides the blinking time.
Values are not critical, but this is a good combination.
Edit: 23th November 2014
Someone asked me more info about the resistor to play with.
The last time I played with this toy was a long time ago, however, all information needed is pointed out by the tow green pepperoni below. The original resistor is missing and the two white wires are connected to the potentiometer in series with the photoresistor.