My daughter just had a giggling fit after rolling over for the first time! Unfortunately neither of us saw her do it. She was doing tummy time with Mr. Haa and he got up to get a soda from the kitchen. When he came back she was on her back! We spent a bunch of the afternoon trying to get her to do it again. During this process she started to get upset so we flipped her on her back and started tickling her and being silly. She started giggling even cuter than that laughing baby on youtube.