One of my favorite trends in all of film and television is the cast sing along. That moment in a film or television show where a song comes on and unites the cast, usually through their pain, showing them all singing the song in various locales. It's not done very often, and a few of my entries here fudge those qualifications, but there's no denying this is a terrifically underused storytelling device.
Magnolia "Wise Up" by Aimee Mann
The most famous example of this device comes from Paul Thomas Anderson's Magnolia, a film I happen to think is among the best ever made, but which also has some of the most vocal haters of any film ever made. The scene is now probably more famous than the movie itself, and it was even brilliantly spoofed on Community, but for an innovative portrayal of loss and longing, it's second to none.
Skins "Wild World" by Cat Stevens
The groundbreaking UK series Skins was another in a long line of shows that was under-seen and under-appreciated here in the States, but this final scene from the first series remains among the best moments of the entire show. A beautifully orchestrated scene that caps an unforgettable first run.
Sense8 "What's Up?" by 4-Non Blondes
Perhaps the most recent example—and for my money, the most bizarre—came on the first season of the Netflix Original Series Sense8. Perhaps it's the fact that none of these people can sing, but there's just something off about the way the Wachowskis did this scene that just feels off. Nevertheless, it's a great device and they use it about as well as they possibly could given the circumstances.
There's Something About Mary "Build Me Up, Buttercup" by The Foundations
Shot throughout the course of filming, The Farrelly Brothers' gigantic hit There's Something About Mary ended with this music video featuring the cast lip synching to The Foundations' classic "Build Me Up Buttercup" and played over the end credits. It was a great way to send the audience home on a high note, and really captured the spirit of the film better than any interviews or behind the scenes footage.
Hot Rod "You're the Voice" by John Farnham
Again, this one's kind of fudging the rules, but I think this movie is brilliant and this is arguably its best scene. A note perfect spoof of the inspirational musical moment that comes so often in the underdog sports movie, the scene is a genius bit of absurdism.
Anchorman "Afternoon Delight" by The Starland Vocal Band
Finally there's this, which again, probably doesn't belong on this list, but I love it, so it stays!