I don't know what he understands of it, but for some reason the boy in intrigued by Sesame Street. If I recall so was his sister at that age. Now, it's mostly Caillou for her. Anyhoo, if I want some quiet reading time, Sesame Street tends to do the trick for awhile. I don't revert to the TV often or for very long, but it makes for a nice diversion every now and then.
But, unlike sister, he's quite fond of the camera too and can hardly resist smiling for it.