Salem History has a great series, American Decades, that contains encyclopedias of current events and popular culture broken out by decades (the 1940s, 1990s, and so forth). The Great Events from History series can also be helpful.
Full page scans of every page of every issue of the New York Times. Great for looking up reactions to historical events, "hearing" the language of an era, and finding advertisements for current products.
Select American and international newspapers from 1764-present, including The Irish Times, The Jerusalem Post, The Korea Times, The Times of India, and local papers from Cleveland, Dayton, Cincinnati, and San Francisco.