we've been playing this game quite regularly for at least a few days now. "how big is milo?" and we don't even do the movement ourselves, he just waves his hands and arms around above his head and smiles triumphantly.
he's also started initiating peekaboo games. when i catch him "hiding" - putting his head down on his high chair tray, holding anything in front of his face, pulling a blanket over his head - and i ask "where's milo?" and then he proudly "reveals" himself, and i act all surprised with an exaggerated "peekaboo!"
we're also pretty sure he understands no - at least to some extent. when i get to the part in his "moo baa la la la" book that goes "no no, that isn't right" he'll shake his head no. and when we tell him "no no" when he's in the middle of doing something he knows he's not supposed to - like pull all the dvds off the shelf, or grab the kitty's fur, or hitting the tv - he shakes his head no. sometimes i'll look over to him about to do one of said offenses, and he's shaking his head no - and smiling of course - in anticipation of us telling him "no."
he's such a cheeky little monkey.