Yesterday I got an email from Jason asking if I wanted to go to a movie that evening, Cineplex was having a 'Blue Monday' special where it would only take 500 points to see something in any theatre. (Normally it is 1000-1500 depending on the type of theatre.) We decided to see Star Wars: Episode IIV - The Force Awakens again.
Not only did the promotion work for us, good job advertising, but the promotion is also based on an advertising created concept, double points. Similar to diamonds and engagement rings, the concept of 'Blue Monday' was created for a company, by an advertiser, in order to sell something. This date gets referenced every year and there is no actual science behind it.
Check out the CBC Article that describes the pseudoscience used by a travel company to market the end of January as a good time to book a vacation.