He's spent one month doing a modified breast-stroke across the floor, but that's happening less often now that he's learned to crawl. He's taken individual crawl "steps" for a while now, but yesterday was the first time he just got up and crawled across the room.

It's not on this video, but he's also getting pretty good about pulling himself to a standing position using all sort of things. His balance is also getting better-- he can walk while only holding one of our hands now instead of needing to hold both hands.