To download this and other clips off of YouTube, I recommend, as always, the YouTube Downloader HD program. For other videos I've used and the skeletal lesson/activity plans I've built around them, check out the Multimedia Monday tag.
David Armand is one of the funniest comedians I've seen in a while. He's done a whole bunch of "interpretative dances," and while they're all hilarious, unfortunately only this one is unequivocally appropriate for a young class. (The others either have references to sex, genitalia, or both.) Any time I have a chance to show something in class that I like watching? Everyone wins.
You can print out the lyrics before, if you want—that's probably helpful for lower-level classes. With more advanced students, you could easily make this a game. It'll take a bit of advanced planning, though. Write "I'm never gonna dance again" on the board, cue the video up to the chorus (with sound), and hit play. In this video, it's at about 40 seconds in. It helps if you point along to the words: once I did that, my kids sussed out right away what Armand was trying to convey.
Then, back to the beginning, and kill the sound. Maybe watch it twice. Have the students write what they think the lyrics are based on Armand's mime routine, and then pass out the lyrics so they can see how close they got it. (I admit, I haven't done this part yet, as I don't really have the time for it in my advanced classes. But I've got it ready, just in case I ever do.) If you have the time, you can play the video one more time with the lyrics so they can try to match the mimes to the real words—have students circle the words at parts where they didn't understand the mime, and so forth. Considering how damn popular George Michael's Last Christmas is in Korea, I'm sure Korean students will take to Careless Whispers fairly readily.