It's a Wonderful Life. Right at the end. "Atta boy, Clarence." Christ, always gets me.

NSFW!

https://search.creativecommons.org/
Then use the soundcloud search. Just check the Creative Commons license that the uploader has given. Sometimes it is Attribution for example, so you need to just credit them in your work. Sometimes you can't alter or remix the original track which is obviously a pain for us filmmakers unless you're doing a music video for that song!

Dying to know the results!

Great idea for a music video. And perfectly executed!

When I was at uni this very same question came up and this is the example our lecturer gave us.
https://www.youtube.com/watch?v=9hwKjE8dVJ0
I think the gist would be to make sure that there is an shot establishing the space (not shown in the link is the scene where everyone sits down) establish the space, then once in there break the scene down into miniature conversations/scenes. I forget character names, but e.g. when Steve Carell and Greg Kinnear have a little interchange the shots are standard over shoulder, shot-reverse-shot and they set up a little individual 180 line between them.
Then when Steve Carell and Abigail Breslin resume their conversation it goes back to their 180 line.
I think that's the basics, just stage a bunch of 180 lines in between characters that are directly interacting, have some covering reaction shots (Toni Collete's main shot is from between Carell and Kinnear as that's who she is mostly interacting with (and metaphorically stuck between) but she also has a shot with Breslin's 180 line when interacting with her).
Long story short, establish the space then get shit loads of coverage.