
Two examples, though there are dozens out there.
I've been thinking that the first example could quite easily be parodied and re-titled "The Sequestration Song". Such appropriate lines: "Don't you love farce?" (Usually I do but not when the players are supposed to be running a country!) ...."Quick, send in the clowns - Don't bother they're here"
Send in the Clowns, one of Stephen Sondheim's best known numbers. It comes from his show A Little Night Music. The story behind it tells of a middle-aged couple who split up because the female wishes to; the male finds another love, a much younger woman. The middle-aged female then finds she loved the guy all the time and tries to get back together with him, but .....no go, he's in love with his "child" bride. Here's a version of the stage show original with Judi Dench in the middle-aged female role:
Here's what happens when Stan Kenton and his Orchestra get a hold on it....it's bent and stretched, and even sounds a tad classical in places......but the same melody remains at its heart.
Second example:
My Funny Valentine a song written Richard Rodgers and Lorenz Hart in 1937 for a musical: Babes in Arms. The song has been recorded my numerous vocalists keeping the original flavour intact: Linda Ronstadt's with Nelson Riddle's orchestra is a classic version. Miles Davis did his "thang" with it (link), as did many other jazz musicians. The music's quality never deteriorates, because something about the original has elasticity, resilience, an innate magic. Husband says it's all in chord structure, but I believe it's a tad more esoteric than that.
Paul Desmond on alto-saxophone did it his way:
Musical tradition is important but not fixed.
It evolves through encounters.
A Tibetan Master quoted by D. Rothenberg