Dublin Castle. Something of a disappointment. Only parts of two of the original towers remain. The rest has become government offices.
Guiness Brewery water from the Wicklow mountains. Guiness made a special point of emphasizing the water did not come from the River Liffey (perhaps because Guiness looks so much like Liffey water).
The only way to see Dublin. With a pint in hand from atop the Guiness St. James Gate Brewery. This bar had a 360 degree view and seemed to rotate to at least some of the inhabitants.