Garage: A Rock Saga.

George Wendt yells at a young man in a restroom for not being half the man his dad is. The young man walks out of the restroom and into his dad's funeral and forms a band whose sound changes over the decades while they constantly fight. One member joins a Satanic coven, then gets into God, and there's an alternate dimension version of MTV that brings the goods. This film commits to its line and tows it all the way. It is hilarious, full of wit and has great music. No joking.