And in no particular order:
2. The Aretha Franklin scene (or any other scene) in the Blues Brothers
3. The huge jam session at the close of the otherwise terrible Blues Brothers 2
4. The choral competition in Sister Act 2: Back in the Habit with Lauren Hill (and Jennifer Love Hewitt)
If you're in a bad mood, I defy to to sit there smileless and watch these musical numbers.
"Nobody gets outta here without singin' the blues."