"Red Cup Day," a favorite Starbucks holiday tradition that offers customers free reusable cups, takes place this week -- but there's a catch.

Starbucks Red Cup Day has become an unofficial harbinger of the holiday season for fans of the coffee chain. Here's a look at what makes Red Cup Day special.

Holiday drink season has arrived with cafes and restaurants across the country now serving peppermint, gingerbread and cookie-flavored beverages in "red cups." Why it matters: Businesses are capitalizing on holiday cheer to create a buzz and drive sales.