The Wanker Triplets
Identical singing triplets from the "All In the Family" episode (05/01/1988) of Married with Children.
Played by REAL identical singing triplets, Del Rubio Triplets (Milly, Elena, & Eadie). Visiting relatives of wife Peggy Bundy (Katey Sagal), they sing "You Are My Sunshine," Al gives them bad advice, and then just sorta stand around in the background.
See also The Donatello Triplets, another fake band played by The Del Rubio Triplets.