O'Flanagan's Pub is a bar in Dunkilderry, Ireland that has existed since World War II. It is owned and named after Tom O'Flanagan. When Grampa was young and he used to come to the pub, it was really popular: people danced and sang at the pub. The Simpsons visited the pub and again discovered it declined when people in Ireland started working. Homer and Grampa bought the pub after they got drunk with Tom. They renamed the bar to "Simpson & Son's Pub" and allowed people to smoke inside, the reason it became popular again. It possibly closed down after Homer and Grampa were arrested and deported back to America.
The interior is the same as any bar, with the exception of a room in the corner with a TV and various tapes.
They also used to have a Star Turn when celebs used to come in and perform something like men singing with their guitars or banjos and many, many drinks but from different parts of Ireland. It's a real proper Irish setting.