You've got to hand it to the Irish: They spend so much time thinking about Guinness that they have rules. It should take exactly 119.5 seconds to draw a pint. The head must protrude above the rim but never spill over. The pint should be served at precisely 42.5 degrees Fahrenheit. Each sip must leave a tidal ring on the inside of the glass. And the shamrock drawn in the foam with a fine stream from the tap should reach the bottom of the glass intact. Now, we didn't time our man Darren at the Tipperary Inn. Nor did we take the temperature of the beer. But darned if those rings and that shamrock didn't show up every time--well, the first five or so. After that it's a little bit hazy.