From the Realbeer newsletter:

OLDE FROTHINGSLOSH RETURNS Pittsburgh Brewing Co. plans to celebrate the 50th anniversary of Olde Frothingslosh - the "pale, stale ale with foam on the bottom - with a limited edition can commemorating the beer that began as a joke. In 1954, Pittsburgh disc jockey Rege Cordic created a series of zany commercials for the fictitious beer, Old Frothingslosh, The Pale Ale for the Pale State Male. Pittsburgh Brewing Co. celebrated the gag by putting Old Frothingslosh labels on 500 cases of Iron city Beer bottles for friends of the company for Christmas. The next year Old Frothingslosh had new labels for Christmas and was sold to the public for the first time. The Christmas issue became a popular tradition and over time distribution ranged well beyond Pittsburgh. The beer was advertised as "so light, the foam's on the bottom" and as "brewed from hippity-hops on the banks for the Upper Crudney in Lower Slobbovia." It debuted in cans in 1968 with the introduction of Fatima Yechburg, a 300-pound go-go dancer who became Miss Frothingslosh, and was sold for decades. http://www.realbeer.com/news/articles/news-002425.php