The Flintstones S01E19 - The Hot Piano

To commemorate his 10th wedding anniversary (which he only remembers because it falls on "Trash Day"), Fred wants to buy Wilma a Stoneway piano, but after unsuccessfully dealing with snooty clerk Frank Nelson in a high-end music store, he finds a great deal from a shady, cash-only businessman named "88 Fingers Louie." Fred later realizes that it's more than he bargained for. This episode includes the catchy "Happy Anniversary" tune, sung by a quintet of four police officers and Barney, who is also playing the piano.