15
Guess the Episode [Medium]
(sh.itjust.works)
1 point for the episode/main plot. 1 point for the joke/scene.
Also points are made up and don't matter.
That's "Lisa" performing the "I Want Candy" song as part of "The Simpson Family Smile-Time Variety Hour", which itself was part three of "The Simpsons Spin-Off Showcase" episode.
And the name of the dance is the Peppermint Twist! (Correct!)