Ireland's Four Provinces (4P's) is near the Cleveland Park Metro station, not really near Georgetown. If you're around on a Monday, check out the weekly session at Nanny O'Brien's, convenientky located just across the street from 4P's. For my money (a considerable amount of which has been spent in the various Irish pubs of this fine city) Nanny's is the best pub in the area and the music is always excellent. Best pint of Guinness, as well.