According to the online Urban Dictionary at www.urbandictionary.com, the phrase
“Be there or be square” has the following meaning:

A square being a nerd, geek, dork…un-hip, un-cool, unpopular, not with-it, etc. …sort of person…”be there or be square” means about the same as “everyone who is anyone will be there”, which is to say if you’re not there you’re nobody.

The word “Square” didn’t always have this meaning in reference to a person’s character. Here’s some history on the word from The Phrase Finder website: Immediately after World War II the word “square,” which had long meant honest, direct, solid, became the antonym of hip or hep or sophisticated, at least in the U.S.A. Someone who didn’t like or pretend to understand jazz and swing was “square.” The word came to have a somewhat broadened use as out of touch, conventional, old-fashioned, not “with it.” The latter expression is as dated as “Be there or be square,” which I think was big in the 1950s.

As early as 1804, however, square had come to mean fair, honest, as in ‘square fight,’ with ‘square talk’ coming in 1860, ‘square deal’ appearing as a card player’s term in the 1880s, and square shooter in 1920. However, it was Theodore Roosevelt who popularized the term ‘square deal’ in its general sense.

There are a couple other phrases that I can think of that show the word “Square” in a better light, for instance:
- Square Meal
- Fair and Square

To this day, you still hear this phrase being thrown about from time to time, just like “See you later, alligator” (ahh, another future post!).

I remember seeing an old Flintstones episode where Fred became cool with the kids because of his singing, but Wilma got tired of his new found fame and tried to turn the tides so kids would think he was a “square”.

Check out this YouTube video when Wilma spreads the rumor during one of Fred’s shows.

http://www.youtube.com/watch?v=u1DX3hw_9A0

This was episode 15 called “The Girls Night Out”, which originally aired in January 6, 1961. Here’s a description of that episode: “Fred and Barney decide to treat their wives to a night out, at an amusement park. Fred cuts a song at a recording booth as a souvenir but misplaces the record. It is later discovered by a group of teens who pass it along to a DJ, and Fred is suddenly transformed into unwitting rock star “Hi-Fye.”

I guess good ol’ Sponge Bob “Square” Pants missed a few of those, “Be there, or be square” parties.