Memorial Day just passed but we've been blessed with another holiday today. Unfortunately, this holiday doesn't call for a day off from work but it does involve some free grub. Today marks National Hamburger Day and to celebrate, several establishments are offering some deals that will only come around once in a blue moon -- or once a year. Although it's National Hamburger Day, Dairy Queen is offering customers a solid deal until the end of the month.

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If you're a fan of Dairy Queen burgers, you're just in luck. The ice cream establishment announced that they'll be serving free customers this year for National Burger Day. It does come with a catch, though. You can take advantage of this deal until May 31st by downloading the Dairy Queen app, ordering a shake or a malt, and boom, you get a free burger. There isn't a limit and the deal goes on from May 28 to May 31. Unfortunately, the deal isn't available to those in Texas or in Canada. However, Texas is offering a free Hungr-Bust with the purchase of any shake on their app. 

Jack in the Box, who recently faced a public scolding from Kim Kardashian, is also offering BOGO bugers. If you purchase one burger, Jack in the Box is sending you home with another one for free. It's lit.