Lyrics with chords, from the book Tom Paxton Anthology (first verse only; the others are the same):

 Am
  Saturday night and the bar is packed.  The
  Em
  drinks are watered and the decks are stacked; the
  Am
  whores are grinning with their faces cracked, and the
  Em
  gamblers cursing at the horses they backed.
  C
  Saturday night and the bar is jammed.  We've
  Em
  got our table and the rest be damned.  The
  C
  waiter's hovering near at hand.  We're
  Em
  loaded earlier than we planned.
  G    Am   Gdim G  C#dim      G7
  Some damn fool is starting a fight.
  G        Am Gdim G   C#dim    G7
  Why does he wait for Saturday night?
  C                                  C#dim
  Mary and Eddie are busy indeed, making
  G7
  up for lost time in the rear.
  G7                           Dm7
  George is beginning to sweat while a
  Gdim     G7 C
  stranger is sticking her tongue in his ear.
  C                                C7
  David's explaining the next revolution.
  F
  Someone is granting the crowd absolution.
  F#dim G7
  Who - ever is running her foot up my leg, I love
  Am    G    Am  Gdim  G   C#dim
  you.  La   la  la    la  la la la la

That G-Am-Gdim-G progression is a bit more harmonically sophisticated than Tom usually gets. It works perfectly, though.