my kid's quirk is that in any down time (and sometimes when it isn't downtime) he will walk around muttering to himself and acting things out (sound effects and all). If interrupted, he will state "Hold on, I just have to get through this scene... I am workign on a [movie] [book] [video game]." He's been doing this for as long as I can remember. It is seeming more and more weird. LOL. He often has entire worlds, conversations scenes, etc going on in his little head. Fortunately, most of DS's friends and classmates now know him as a "writer" and DS will just say I am working on my next movie/book/game. I am not sure if this a quirk or a disorder
