gistfile1.ino

int pushButton = 3;
int lastButtonState = 0;

boolean isOn = false;

void setup() {
  Serial.begin(9600);
  pinMode(pushButton, INPUT);
  lastButtonState = digitalRead(pushButton);
}

void loop() {
  int buttonState = digitalRead(pushButton);

  if (buttonState == HIGH && lastButtonState != buttonState) {
    Serial.println("TRIGGER");
    if(isOn) {
      isOn = false;
      Serial.println("OFF");
    } 
    else {
      isOn = true;
      Serial.println("ON");    
    }
  } 

  lastButtonState = buttonState;

  delay(1);        
}