It would seem that Calvin has a few new tricks up his sleeve. 
It's possible that he is starting to teethe. Either that or he's been watching the dogs too closely, which is a distinct possibility. Either way, over the past week he has been uncharacteristically fussy, and has become absolutely obsessed with chewing everything. It's true that he has always gummed everything in his path, but lately it's gone from gumming to gnawing. And when he doesn't have an object to gnaw on he simply sucks his own lips up and works on those, 
giving him a very different and not altogether humorless new look. He does it so often that we're not sure we know what he looks like anymore - either his lips are in his mouth or something else is! There are no signs of teeth at all yet, but we wonder if it's just a matter of time.
The other new thing that he is doing is a little more exciting. This morning for the first time he started trying to crawl. He didn't get anywhere, mind you, but he was clearly trying all the same. 
It kind of took us by surprise because there was no sign of this prior to this morning's tummy time, but suddenly today that is all he will do while on his tummy. He's not efficient because he hasn't figured out how to lift his head and crawl with his legs at the same time, so while the legs are going like crazy his face is anchored to the floor. Poor kid. Although it could still be months before he crawls for real (he is only 5 months), suddenly we are feeling less confident about the Christmas tree.