Anyone besides me having his child play N-Back?
We played it when I was in high school, but we called it Egyptian Ratscrew.
(Egyptian Ratscrew, or "ERS" in the company of adults, is a card game that, depending on variant, can include 1-back, 2-back, or 3-back, among other simultaneous pattern recognition tasks. With a nonstandard deck of cards with more features, e.g. Set cards, it would be trivial to adjust it to multi-feature n-back.)
Following up on the 2010 study, Jaeggi and University of Michigan people have run a Single N-back study on 60 or so children.
The abstract is confident and the mainstream coverage unquestioning of the basic claim. But reading it, the data did not seem very solid at all - I will forbear from describing my reservations exactly; I have been accused of being biased against n-backing, however, and I'd appreciate outside opinions, especially from people with expertise in the area.
(Background: Jaeggi 2011 in my DNB FAQ. Don't read it unless you can't render the above requested opinion, since it includes my criticisms.)