Anyone who's been online Sunday probably knows it's Star Wars Day, one of the Internet's favorite holidays, during which fans and nerds alike love to say "May the fourth be with you."

Not only are phrases related to the day dominating the majority of trending hashtags on Twitter, brands are capitalizing on it, too. We've seen Major League Baseball players wielding glowing lightsabers, and Nissan getting punny with its new Juke ad. What's more, musicians such as Chris Daughtry and Ben Folds have teamed up with College Humor in a Star Wars-themed parody.

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The phrase, "May the fourth be with you" has its roots in advertising. First used on May 4, 1979, Margaret Thatcher's political party placed it in a London newspaper ad to congratulate her for becoming the UK's prime minister, according to StarWars.com. It said, 'May the Fourth Be With You, Maggie. Congratulations."

But Star Wars Day didn't really take off until about three years ago, when the Toronto Underground Cinema started celebrating it in 2011 at an event that featured a costume contest with celebrity judges, as well as a marathon of Star Wars tribute films, mash-ups and parodies, according to International Business Times.

Here's a look at some of our favorite May 4th references, which made the rounds online Sunday:

Southwest Airlines

Oreo

This milk was way too cold for a golden bikini. #MayThe4th pic.twitter.com/vRtOewcgCM — Oreo Cookie (@Oreo) May 4, 2014

Windows

Starbucks

Hormel Bacon





College Humor: Star Wars Cantina Band auditions

Nissan Juke ad

Crayola

Post by Crayola.

Smithsonian

He's from a galaxy far far away but he's still a national treasure http://t.co/hCN34xHnip #MayThe4th pic.twitter.com/2vfVrH2MZv — Smithsonian (@smithsonian) May 4, 2014

MLB: The Empire strikes out

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