There's a playful element to most of Nauman's work that really makes me smile. For example, there's a video installation he did called Double No that's kind of hard to explain... basically, it's two TV sets on top of each other, each displaying an image of a jester saying "no no no no no no NO!!!" while jumping up and down, making that kind of angry body noise you see in small children. The bottom set shows - if I remember correctly - the same image as the top set, but inverted. Very simple, very funny, and mesmerizing.
I'm also a big fan of another one of his video pieces that features actors staring into the camera, reading the same sentence over and over, but with grammatical variants [I, you, he, she, etc.] and/or different inflections. It reminds me a lot of an a track on the first You've Got Foetus On Your Breath LP, Deaf, entitled What Have You Been Doing? That Foetus track built on a woman's voice repeating the same sentence, emphasizing a different word each time; after all, What have you been doing? means something different than What have you been doing? The repetition is again hypnotic, and it also speaks volumes about the nature of language. Or, rather, at least it does to me.