The Lord of the Rings: The Two Towers:
The siege of Lisa and Bart's box fort is a direct homage to the siege of Helm's Deep in the second film of Peter Jackson's Tolkien trilogy. Bart and Lisa are outnumbered greatly and before the battle Bart even utters a dismissive comment along the lines of "Is this all you can summon Sauramon?" Nelson shows up at the last minute to provide much needed re-enforcements as do the Elves in the film. There are many specific references to actual scenes of the combat in the film, most specifically the very tall scaling ladder which is pushed back down by Bart as it carries several attackers.