there's only about 2 or 3 bars on Barra. The Castlebay Hotel (in Barra's only settlement of any note, Castlebay) has a bit of a good reputation but it was very quiet the one and only time I've been there, during the week last summer. There is a music festival every year called the Barra Feis though and then the island is supposed to be absolutely jumping. Barra is great though, lovely beaches, lovely people, and the view from the hill behind Castlebay is amazing.