From Homestar Runner Wiki
Litigation Jackson is a film that helped to sponsor the Decemberween Pageant in the 'toon A Decemberween Pageant. The tagline is "This Decemberween... The System Really Works, Jerks!" It was released into theaters on December 27th.
According to the film's poster (starring Matt), it is a joint project between the famed Free Country, USA jack-of-all-trades writer/illustrator Lem Sportsinterviews and one of the Delabors of Thorax Corporation, most likely Gent Delabor as he is the head of the company and seems to do most of the work. It was brought to you by the makers of Trogdor and the Peasant's Quest movie.
A sequel was revealed in the email "rampage," entitled "Litigation Jackson 2: Legal Rampage." The poster features Litigation Jackson holding some "Important Legal Documents", implying higher stakes than the box of plain old "Legal Documents" in the original film (see poster) with an explosion occurring in front of the New York Supreme Court. He appears to have gotten a perm between the first and second movies.
The name "Litigation Jackson" first appeared in the game Hairstyle Runner, in which one of the hairstyles in the gallery is entitled "Litigation Jackson". The hairstyle features a unibrow and a goatee and sideburns that both resemble the letter J.
The parody refers to the title of the 1988 film Action Jackson.
To "litigate" means to contest or engage in legal proceedings.
The entire series could be a modified-spin off from "Litigation Johnson", a name under the testimonies for Thorax's "PROGRAM CONGRATULATION(TM)(R)(C)" PRODUKT.