I mentioned In Bruges last week in the Q&A, so I better recommend it here! in Bruges is a terrifically funny film that never the less, has a darkness to it that many films wouldn't dare cross.
It's not just a brilliant directorial debut by Martin McDonough (who also did Seven Psychopaths, another film I've recommended), it's just a flat out great film with some of the best performances by every actor involved, Colin Farrell in particular. Martin was nominated for his screenplay, but Colin definitely deserved something too.