We have a lot of laughs around here. He's really getting into initiating games of peek-a-boo, with him being the one to hide his face. He laughs easily, and when caught off guard will check to see if we're laughing and will join in if we are.
Dave has had to reconfigure his computers. He's got an elaborate setup with various machines under his desk. Christopher's playpen goes part way under his desk, and the bars are far enough apart that he can reach quite a bit of the perimeter. Twice now he's reached over and pulled Dave's hard drive right out of the computer while he was using it. Ouch. Some data was lost, but Dave moved things around so now all Christopher can do is drum on the top of one of the disused metal computer boxes.