Coloring

 All he wants to do is color. The faces this kid pulls while doing it are priceless.  He goes through coloring books like they're going out of style, and won't color with anything but markers (and the content he is coloring has to have either Mater, an airplane, or a car of some sort). Seriously, the other day he sat and colored for over two hours straight, and the day before that was an hour and a half.  

Although I am thrilled he asks to do something besides watch Cars 2 or make cookies all day, it is becoming quite expensive to keep coloring books and markers with the tip not bitten off in stock. (The 'eating markers' thing just started yesterday.  We're working on it.)