On August 8, 1976, in the first game of a doubleheader at Comiskey Park in Chicago the White Sox took the field wearing shorts as they took on the Kansas City Royals in the first game of a doubleheader. The idea to dress up like a mailman to play baseball came from Bill Veeck who had purchased the team one year earlier. After purchasing the Sox, Veeck had several ideas for uniform changes to make his new club the class of Major League Baseball. In March of '76 the owner had several of his players show off several new looks to the media in a catwalk style event, most of the new uniforms were a little different but nothing drastic until Jungle Jim Rivera came trotting out in his blue bermuda shorts, I'm sure the reporters chuckled when they seen the White Sox first baseman in his new digs. When the game rolled around in early August the White Sox were 19 games out of first place and Veeck saw an opportunity for a boost in attendance by making his club wear the shorts. The result was a good one for the club from Chicago, they might have looked all jacked up but they won the contest 5-2 over the Royals. Two weeks before the game was played second baseman Jack Brohamer said the only way he would wear the shorts is if he could wear a halter top too, coincidentally Brohamer knocked in what proved to be the game winning runs with a two rbi single in the sixth. Simply put the shorts unis might have been the worst uniforms of all time, the Sox lost the second game of the doubleheader wearing pants so maybe the shorts helped them get the job done. It was a short lived gimmick, they wore the shorts two more times before the idea was scrapped and they went back to a traditional uniform, I'm glad they did.
Here's the box score from the shortastic game: http://www.baseball-reference.com/boxes/CHA/CHA197608082.shtml