In the end concert which recreates The Beatles' rooftop concert, Homer is dressed like Ringo Starr. In "Brush with Greatness", which Beatle was teenage Marge infatuated with? Yes, Ringo.
Also doubles as Fridge Horror: we never learn what happened to all the money that Homer made during his musical career but given the Simpson family's Perpetual Poverty, it's most likely Homer blew it all.