Bob sings H.M.S. Pinafore

When it seems that Bob has Bart cornered, he asks the boy if he has any last request. Being on a drifting houseboat, Bart takes advantage of this, and tricks Bob into singing the entire score of H.M.S. Pinafore. Sideshow Bob complies to this request, distracting him long enough for the boat to reach Springfield, where the cops are waiting.

Example of:
Scheherezade Gambit