Tab A into Slot B
A phrase Mark uses to describe a functional, if not particularly inspiring, piece of filmmaking. The film in question is usually an example of a well-trodden genre, such as an action or horror film, and the film conforms to the expectations of that genre.
The phrase refers to the instructions one might find on a self-assembly model, where cardboard tabs fit into pre-cut slots. Oddly, such instructions usually match up slot and tab labels, so Tab A would normally fit into Slot A.
See Also: Does what it says on the tin