Attiny13 External interrupt

Hi,

Just past the beginner stage, now I am trying to use the Attiny13 (internal clock, 1 MHz) to respond to an external interrupt (PCINT0).

I am simply trying to get the Attiny to register a high on PIN 5, and in response, get an LED to blink. It works, but randomly. And when it does blink, it's way less than the approx 1 Second delay I was expecting. I am using a tactile switch to connect PIN 5 to vcc to send the interrupt.
Not sure what I am doing wrong here. Hope I am not way off the mark!

void setup() {
  pinMode(3, OUTPUT);
  //pinMode(0, INPUT);
  attachInterrupt(0,pinHigh,RISING);
}

void loop() 
{

}

void pinHigh()
{
  detachInterrupt(0);
  blnk(1000);
  attachInterrupt(0,pinHigh,RISING);
}

void blnk(int n)
{
  digitalWrite(3, HIGH);
  delay(n);
  digitalWrite(3, LOW);
  delay(n);  
}

Any pointers please? Thanks a ton!