The phrase identifies a specific type of holiday-themed collectible item: a countdown calendar, structured around the sport of professional American football, featuring miniature vinyl figures manufactured by Funko. Each day leading up to a holiday (typically Christmas), a new figure is revealed, contributing to a complete set of characters or items.
The popularity of these calendars stems from several factors: their combination of sports fandom, the appeal of collectible figures, and the excitement of daily reveals. They provide a unique and engaging way for enthusiasts to celebrate the holiday season while simultaneously expanding their collection of sports-related memorabilia. This type of product often sees heightened interest during the holiday shopping season.