http://moviehole.net/201479805legion-of-superheroes-movie-in-the-works

Not content with letting Marvel make a moolah from their recent cinematic take on a space-based superhero outfit, Warner Bros are looking to do a “Legion of Superheroes” movie.

A 30th century superhero club inspired by Superboy, the Legion of Superheroes featured such intergalactic heroes as Lighting Lad, Saturn Girl, Comisc Boy, Karate Kid, Wildfire and the aforesaid Superboy.

Says Latino Review :

According to sources, Warners is quietly sending out the DC comic book Legion Of Superheroes to screenwriters & their reps for takes. For non-industry folks, what that means is that screenwriters check out the comic book and come up for a movie idea involving the characters from that comic. Those writers then go to the studio to pitch their idea. The studio then hires the screenwriter they feel has the best idea or take for the film.

The Legion of Superheroes first made their appearance in Adventure Comics #247 in 1958.