cannonball Sunday
n.— «On these great festivals of the Christian faith, churches are crowded, often to overflowing while on some other Sundays the exact opposite is true. In fact, the Sundays after these great festivals are sometimes referred to as “cannonball Sundays,” meaning you can fire a cannon through the congregation and probably not hit anyone.» —“Spirited Words” by Alan Kimber RecordNet (Stockton, California) Dec. 25, 2004. (source: Double-Tongued Dictionary)