The common story is that alternative and often humorous rock band known as They Might Be Giants took their name from a 1971 movie, but the truth is much weirder.
The group known as They Might Be Giants consists of the two Johns - John Flansburgh and John Linnell. The two Johns knew each other in high school and began writing songs, but their group did not develop until 1982.
They Might Be Giants has been a very popular alternative band with their biggest success arguably being their 1990 album "Flood." They have also released three children's albums to date, with much critical appeal. The band's undeniable hooks and witty word-play have created a very large cult following, making them one of the most popular acts for everyone from elementary aged children to recent college graduates to aging hipsters.
The band's success, and muted mainstream glory, sometimes is considered to be an extension of their admittedly odd band name. Many rock critics who had never seen the band perform live assumed the name was taken from something in pop culture. Upon some basic research, one editor from Rolling Rock decided it must have come from the 1971 movie of the same name starring George C. Scott. It made sense, as the John's lyrics often belied a duo whose intellect would be attracted to a "Don Quixote" reference, as that movie did.
The problem is that this myth has continued to be perpetuated by those who have never seen the band in person. The main reason for the two Johns becoming friends and writing partners, and later bandmates, in the first place is that they are both members of a long-thought-to-be-mythical race of giants.
Giants are common in mythology and religions the world over. Even in our current times, the idea of the giant holds a large place in our culture. Recall the childhood tale of Jack and the Beanstalk. Or look at the vegetables in your freezer with a Jolly Green guy on the packaging. Or refresh your education about the giant lumberjack Paul Bunyon and his blue ox Babe. And, of course, in the Judaic-Christian tradition, there is the popular tale of David defeating the giant Philistine Goliath. In Greek Mythology, the Giants were defeated by the Olympian gods and often buried underneath volcanoes. In fact, large fossilized bones (usually dinosaur bones) were often considered to be the ancient bones of giants when first discovered.
But the story doesn't end there. Apparently, not all giants perished. A small handful escaped the wrath of the Olympian gods and made lives for themselves on Earth. They mostly evolved into a smaller species to fit in with humans. But, some retained their size and even found respect in some athletic circles - for example, some early professional football players on the New York Giants (such as Frank Gifford and Pat Summerall), the occassional basketball player like Shaquille O'Neal, or André Roussimoff, rest his soul.
When John Flansburgh and John Linnell met as teenagers, they bonded over their physical size and shared history as giants. When they finally created a band, they decided on a name which paid respect to their ancestors. However, as is common in the giant community, the two Johns had a great fear of retribution by Zeus and the other gods of Mount Olympus. So they decided to be playful in their name themselves, not outright declaring their gigantic status, but stating they "might" be giants. And music fans everywhere are grateful for it.