Cocktail Party Fact: Mozart originally included a second minuet before the slow movement of his famous “A Little Night-Music,” but he later changed his mind and the movement is now lost.

Commitment Factor: About 18 minutes.

Vital Statistics: Classical Period. A four-movement work for string orchestra.

What to Listen For: This beloved composition is so familiar to most listeners that its features don’t need much in the way of pointing out. Just sit back and enjoy. While you’re at it, though, the first movement of Eine kleine Nachtmusik features one of the clearest examples of “sonata form” or “sonata-allegro form” ever written, so here’s your chance to find out what it all means.