I think the best place to go, if you are of that persuasion, is the little seaside town of Sitges, about 45 minutes south of Barcelona. This is supposedly the "gay capital" of Spain. Last time I was in Barcelona, I did do a day trip to Sitges and it is really a quaint little town but definitely unconventional, to say the least, specially in their nightlife. However, if you are the least bit inclined to homophobia, Sitges is definitely NOT the place for you.