The League of American Theatres and Producers, a trade organization representing Broadway and regional producers, is located at 226 West 47th Street, just off Times Square. But if you look up before you enter their building, you'll see an old, folksy sign reading "The Theatre Guild" and featuring a depiction of a thin, Tudor-style house.
The Theatre Guild was once a dynamic force in the history of the American theatre. It was founded in 1919 by Theresa Helburn, Lawrence Langner, and other artists. Between the wars, it produced dozens of challenging and noncommercial plays, seriously improving the quality of the fare that was then seen on Broadway. It fostered the work of Eugene O'Neill, Robert Sherwood, S.N Behrman, Maxwell Anderson, Sidney Howard, William Saroyan, and Philip Barry. The Lunts and many other fine actors called the company home, and they built what it now known as the August Wilson Theatre specifically for their purposes.
Artistic spats led to two important splinter outfits, the Group Theatre and the Playwrights' Company. The Theatre Guild probably would have gone under in the early '40s, but its fat was pulled from the fire by a little show called Oklahoma!. It faded in importance in the 1960s and 1970s. Their last gasp on Broadway was an ill-fated production of the musical State Fair in 1996. Why the sign remains, I do not know. Theatre community sentiment, I expect.