What Are the Only Two Days of the Year on Which No Professional Sports Games Are Played?
The only two days of the year on which no professional sports games are played in the United States are the day before and the day after the All-Star Game for Major League Baseball. As of June 2014, the All-Star game has always been played in the month of July.
While Major League Baseball does hold its annual Home Run Derby on the day before the All-Star game, the event isn't considered a professional game but rather a contest among many of the league's top hitters. Baseball players who don't take part in the Derby or the All-Star game have those days off.