Plug the Photoresistor in the extensions port to GND and to PIN19.
This code plays a permanent tone, which get as higher as less light is hitting the photoresistor.
#include <gamekit_2_1.h>
int light; // variable for the senor value
void setup(){
gamekit.Begin();
// enable pull up resistor for analog in
digitalWrite(19, HIGH);
}
void loop(){
light = analogRead(5);
gamekit.play_tone(light, 100,LOUD);
}