The New York Public Library Digital Collection offers a wonderful online exhibit of billboards and advertisements from the Yiddish theatre.  You can visit this site and enjoy all of this wonderful memorabilia at http://tinyurl.com/22f2ta 

The Web site is very simply in design. All you have to do is click on your choice of link, and then virtually flip through the entire collection.  I spent a very happy hour enjoying these works of theatrical art.

Michael