The Austin-shot movie Zero Charisma may be as close as we ever get to a cinematic adaptation of A Confederacy of Dunces. Scott Weidemeier, as portrayed by Sam Eidson, bears a strong resemblance to a contemporary Ignatius J. Reilly, if Ignatius were transplanted to a lesser city than New Orleans and had been introduced to role-playing games like Dungeons and Dragons. (Which leads me to ponder an Ignatius-approved RPG set in the time of Boethius, but I digress.)
What makes Zero Charisma so watchable is that Eidson and filmmakers Katie Graham and Andrew Matthews lead us to sympathize with a character as appalling and unlikeable as Ignatius would be, if we encountered him in real life. Scott is living with his grandmother in a glorious Fifties time capsule of a bungalow (with decor that would close Ignatius's valve), working as a delivery boy for the Donut Taco Palace, and in the rest of his spare time, creating and playing his own D&D-like role-playing game in which, naturally, he is the Game Master.
Scott's life is pretty routine until Fortuna spins her wheel and two horrible things happen: one of his regular RPG players drops out of the years-long game, and his grandmother suffers a stroke that brings Sam's mother (Cyndi Williams) and her husband back in town and invading Scott's sanctuary. He finds a new player, Miles (Garrett Graham), but Miles turns out to be a rival for the attention and perhaps allegiance of Scott's regular players.