Can anyone describe theater in the 1920s, without saying that broadway was a big deal?Mostly theater that was provacative. Flappers, vamps, ect.

The previous answer is really good, American serious theatre was breaking away from European traditions.  But the most common theatrical presentations in America were not serious art, or musicals, but what was termed "vaudeville."  These were short acts; musical, singers, comedy, one-act plays, dancers, jugglers, acrobats and animal acts.  Most of he great comedians,singers and movie stars of the 1930s through the '60s had usually begun in vaudeville, which flourished from the late Victorian period through the 1920s.  The Palace in Times Square was the top venue for vaudeville, eight acts a show, two shows a day.  Although many of the performers enjoyed a social status just above vagrants, some were rich and famous, such as comedian Walter Kelly (Grace Kelly's uncle) and Scottish minstrel Sir Harry Lauder.  Charlie Chaplin, the Marx Brothers, Mae West and all six of the "Three Stooges" came out of vaudeville.  It may have been more low-brow than the legitimate theatre, but it was "respectable entertainment" for the masses, and the theatre that the vast majority of the populace saw.  The rich, famous and powerful were often fans, too, such as Woodrow Wilson.