If memory serves me right, I let out my first giggles when I was four months: July 3rd, 2008 to be exact! :))
The first time Mommy heard them, she was so happy! I guess it came quite unexpectedly because I was having a fit and was crying so much before it happened. Mommy must have been tired at that time because she wasn't able to capture me on video. She was able to record my giggles though, so that Daddy can also hear them. And I saw Mommy smile at me affectionately when I giggled to her. So I guess I was able to take away her exhaustion the first time she heard me. And for that, I am happy!