See also: List of K.K. Slider Songs
K.K. Slider is a guitar-playing dog whose music just wants to be free. He will be in The Roost, which is the café in the Museum, every Saturday night. He will play a song for you. You can either request a song (if you know the names of his songs, which you might from a neighbor's music player), or he'll just play a random song for you. After his performance, you can talk to K.K. to get a copy of the song.