There is a cartoon/manga called Oshiri Tantei ("Butt Detective") that the boys like.

Oshiri is a crack detective. Not one to take a backseat or sit on his duff, he always gets straight to the bottom of any crime and find out who's behind it--no ands, ifs, or butts, about it. Best part about Oshiri, is his character: he's never an arse or cheeky, though he can be somewhat stern.