We were watching The Sound of Music a few days ago, and we realized that The Blues Brothers movie is basically The Sound of Music, set in Chicago with the blues.
Eerie coincidences, woooooo:
It's a musical.
The protagonist(s) are on a mission from God, each directly from Catholic school/abbey, and sent by Mother Superior.
The Von Trapp children are essentially Murph and the Magic Tones.
The kids/musicians are being promoted for a big show, throughout the entire movie.
They're being chased by nazis.
Cab Calloway parallels the Von Trapp uncle who is a concert promoter.
There's also the jealous and evil girlfriend in each film: The Baroness in TSOM, and Carrie Fisher in TBB.
There's a happy ending in both, except for Jake and Elwood ending up in jail... But -- the Von Trapps escape into the mountains and Jake and Elwood get the money needed for the orphanage.
See, not so weird, is it? It would have been kind of fun if the Blues Brothers and their band did a puppet show. But instead they crashed a shitload of cars in a shopping mall. So there's that.