Pianist Luis de Arquer has established a small chamber company in his 19th-century Gràcia home. It's called "the smallest opera house in the world," and that's probably right since the performers are almost sitting on your lap as they do small-scale productions of opera buffa and bel canto. Shows usually begin at 9pm, but call to confirm. For the true music lover, this could be your most charming evening in Barcelona.