This day in music history.

May 20, 1966, The Who is scheduled to play a show at the Ricky Tick Club in Windsor, England. John Entwistle and Keith Moon do not show up. Pete Townshend and Roger Daltrey go on stage and start the concert with the bass player and drummer of the local band that opened the show. When Moon and Entwistle finally show up in the middle of the set Keith and Pete get into an argument on stage, Townshend gets so pissed off that he smacks Moon on the head with his guitar. Moon quits the band but returns after a week.
Dr. Jekyll and Mr. Hyde by The Who
Someone is spending my money for me,
The money I earn I never see,
In all things I do he interferes,
All I know is trouble as soon as he appears.
Mister Hyde, Mister Hyde, Mister Hyde, Mister Hyde,
Hyde
When I drink my potion my character changes,
My whole mind and body rearranges,
This strange transformation takes place in me,
Instead of myself everybody can see...
Mister Hyde, Mister Hyde, Mister Hyde, Mister Hyde,
Hyde
Whenever you're with me make sure it's still me,
I've got to the stage I can't tell which I'll be,
The loveable fellow who'll buy you a drink,
Then when he's drunk he'll change in a wink
into...
Hyde, Mister Hyde, Mister Hyde, Mister Hyde,
Hyde