He's checking to see if the guy is worthy of entry or not. Saint Peter goes through the books several times, furrows his brow, and says to the guy, "You know, I can't see that you did lots of good in your life but, you never did anything bad either. Tell you what, if you can tell me of one REALLY good deed that you did in your life, you're in." St. Peter, extremely impressed, says, "Really? Wow, when did all this happen?" "Er.. about two minutes ago."