Just two weeks before I cited a sequence in the comic strip Barney and Clyde. In it, the characters first explained the concept of breaking the fourth wall, and then did so. This Sunday, they did it again, but for a different reason. Encapsulated within the sequence is a brief history of Dennis the Menace, and why that comic is less edgy. And the the characters act on that knowledge for the punchline. (click on image to enlarge)
There's a danger of comic strips becoming too self-referential of course, which would further shrink their readership. But for now, these type of gags add a welcome spice to my daily reading.