One of the most popular songs in the world is unexpectedly expensive. Warner/Chappell holds a copyright on “Happy Birthday to You,” which costs anywhere from $500 to $1,500 to use legally, according to Courthouse News. Although people sing it everyday, the song is rarely heard on TV or in movies because of the exorbitant price. It’s bullshit, and it’s about to change.

As The A.V. Club nicely elucidates, the copyright may be nearing its rightful end. Filmmakers from Good Morning to You Productions have been working on a documentary called Happy Birthday, about the song’s origins. During their research, they discovered that copyrights for “Happy Birthday” have either never existed or are simply expired. Now, they’ve filed a lawsuit against Warner/Chappell that its copyright is unjustified. Ars Technica explains:

(Good Morning to You Productions) acquired their own copies of the songbook, including a first edition published in 1916, which didn’t have the song, and versions published 1922 and later, which include it without a copyright notice.

That’s critical, because under the 1909 Copyright Act which was then in force, a published work had to include the word “Copyright,” the abbreviation “Copr., “ or the “©” symbol, or “the published work was interjected irrevocably into the public domain.”

The plaintiffs argue that the 1922 publication without proper notice forfeited copyright in the work. Even if the judge overseeing the case doesn’t agree with them, however, there’s a secondary argument: the copyright for the whole 1922 songbook expired in 1949.

There’s even a third line of defense: even if the work had been published in 1922 with proper notice, and even if that copyright had been renewed in 1949 (which the plaintiffs say it wasn’t), the song still would have become public domain at midnight on December 31, 1997.

Since “Happy Birthday to You”‘s return to the public domain is imminent, let’s take a moment to celebrate some of the best “Happy Birthday” copyright evasions.

Photos via Getty