Sandino's has been the alternative anchor of Derry's nightlife for years. Named after the Nicaraguan revolutionary, it wears its politics lightly and its music loudly. Good cocktails, regular live music, and a crowd that's genuinely mixed in the way that only a certain kind of bar manages to produce. The venue is small and can get busy at weekends, but the programming is consistent and the atmosphere is the real thing rather than a simulation of it.
The kind of bar that every city needs and most cities are slowly losing to chain venues and high rents. Worth a night or a late drink after dinner in the walled city. The music ranges from folk to jazz to something harder depending on the night, so check what's on before you go. Walk down from the Diamond and it's on the left on Water Street.