Jim has taken to banging his head on the wall. Not hard, mind you, but very deliberately. He'll crouch on all fours in front of the wall, and carefully lean forward and bump his head against the wall. Then he looks around and grins at whomever is around to make sure they saw it. Repeat.
Tonight we were all lounging around in bed before his bedtime, and he started to do this on the wall above the pillows. Being the concerned father that he is, Noah demanded some intervention, so, being the accommodating type that I am, I stuck one of the pillows between Jim and the wall just to give the poor bloke some cushioning. Alas, Jim was not to be deprived of his head-banging glory. He sat back on his haunches and carefully removed the pillow (and the one next to it, too, just to be safe). Then he got into game position, took a deep breath, and.... *BOMP* Big grin.
What a weirdo.