The Black Stuff

It's called Guinness (gin-ess, g as in get)
Bought in Pint or ½ Pint sized glasses. The white froth on top is the head and if it's too big it is sometimes called a Bishop's Collar. A sign of a good pint is when you can see the rings of your 'gulps' down the side of the glass. There can be much discussion on good vs bad pints of Guinness, especially the morning after :)

Try it! Ask for a sample if you aren't too sure whether to get the big or the smaller glass.