If you go to Dublin's Guinness Storehouse you get to learn all kinds of cool stuff about how Guinness is made. There is a museum, a bar with a 360 view of the city, a gift shop, and a place that you can pour your own Guinness.
I promise you will never have a Guinness more fresh or better tasting than a Guinness from the tap at the brewery. I live in the states and every time I order a Guinness here I am very disappointed. It does not taste the same!