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

It is Red Cup Day at coffee giant Starbucks, an unofficial holiday for java fans who enjoy discounts and rewards. Here's how it works: Stop by a participating Starbucks store on Thursday and get a free,

Thursday is Red Cup Day at Starbucks, one of the most anticipated days of the year for Starbucks fanatics. The coffee chain rewards customers who order select holiday beverages with a free limited-edition red holiday cup.