Ah well. Wikipedia has deleted the entry for "Klordny". They didn't accept my argument that it's well known within the comics community as valid.
The source of this holiday is DC Comics, which makes DC Comics not eligible as an independent reliable source. Also, any other source contribuing to the facts of the holiday are not independent from that holiday. Even if Klordny (magazine) is notable, it does not make Klordny (holiday) notable. Adding to the article the fact that people know about it, write about it, and have written for a magazine by the same title (regardless of its content) would be original research. Their collective knowledge about the holiday may make the holiday important and famous, but without reliable source material, the topic is not "Wikipedia notable."
The entry is still available at the Legion Wiki, though, which is a much better source of Legion info than Wikipedia anyway. (Or it will be once it's fleshed out more.)
(Previously discussed here.)