Wow, small world, my son is 5 months old as well. He loves when we give him rasberries on his stomach. Peek a boo with a blanket is one of my favorites at the time. It is really amazing watching them develop.

Whenever I try to take videos he stops what he is doing and just stares at the video camera in fascination.

It's funny you mention the hand in mouth activity. My little guy seems to always have at least a finger in there. Funny stuff, thanks for the laugh.