What is so hysterical?

I never was able to get Charlie to sit up for the camera. Usually he practices some in his crib when no one is watching before he'll show you how he does it. When I was putting them to bed tonight he did it once while I had my eyes closed. I was convinced earlier that he must have used the side of the crib for help but as I caught the very end this evening I know he did not. Maybe I can get it on film tomorrow. Instead, I got this great video of Jack laughing at nothing in particular.

My mom was over at lunch today and she, Chip and I were talking about how it might be harder to hold Jack's kind of bottles than Charlie's. So for their afternoon snack, I gave Jack one of Charlie's bottles. He can definitely hold it but doesn't have the tipping part down yet. For some reason the whole thing struck him as very funny. Enjoy!