Once, a young fresher was reading the rules, and was
        more than perplexed at the place where they state:
"All undergraduates, if they are Anglicans,
       must be in chapel each Sunday at eight."
Racking his brains, he began a small rumour that
       spread through the town on the weekdays that followed; he
was not an Anglican, nor Nonconformist; his
       faith and religion was mere Heliolatry.
Saturday evening, our hero retires with a
       smile on his face and his bin at his door,
only to wake to a thunderous hammering,
       made by the porter next morning at four.
Ah, how a little lie, told with great frequency,
       gains repercussions that no-one expects!
"Dawn's almost here, sir, the Chaplain expects you;
       go down to Main Court and you'll pay your respects."

This is no longer the rule, but it used to be.  "His bin at his door" = standard Cambridge signal that you don't want to be disturbed in the morning.