Examples I can think of is "Do the Creep" in The Creep by the Lonely Island, "You're in a loop" in the theme song of the show Looped, those notes after the first line of American Idiot by Green Day (and similarly, those notes after the first line of the Johnny Test theme song).
A weaker form would be in hymns like He is my Portion Forever (in this case, it would be, predictably, "He is my Portion Forever"). I say weaker, because in a given verse of this particular hymn, this line is sung differently the first and second times it appears.
From what I can find online, the closest matches seem to be the "hook", or a "motif", but none of them sound right.