In May, I saw the following line in an article about bicycling, socializing, and social networks in Dublin:
“We just want to show how cycling is a social thing to do and that you don't need to be online to have the craic,” said Elst.
“Craic,” [. . .] or “crack,” is a term for news, gossip, fun, entertainment, and enjoyable conversation, particularly prominent in Ireland. It is often used with the definite article—“the craic.“ The word has an unusual history; the English crack was borrowed into Irish as craic in the mid-20th century and the Irish spelling was then reborrowed into English.
It appears to be pronounced just like “crack.”
The rest of the Wikipedia article is worth reading too; it gives the history of the word, and touches on the controversy over the spelling craic, which has been criticized as “fake Irish” and “pseudo-Gaelic.”