It might be amusing to, instead of focusing on a single movie, do a special episode on a franchise: Specifically any franchise which has more sequels than can be reasonably justified by the initial outing.
For example, Bring It On could reasonably justify maybe one sequel, not four, especially since they are all just retellings of the same story with new casts. American Pie might have been justified doing a couple of sequels, but seven is too many.
There are far too many Police Academy movies. In the Name of the King got sequels. Scorpion King has sequels. It's that sort of thing.