Baby Laughs!

Let me say today is my birthday and it's after 10am and I just woke up on my own cause my husband got up with the baby. Feels good yo. I just wanted to tell someone.

Anyway! On to my real question. My LO is a week shy of 4 months old and he hasn't laughed yet. I'm not particularly worried, but, I WANT BABY LAUGHS! He's chuckled in his sleep a few times and I literally thought my heart was going to explode. He smiles and squeals and coos and gurgles, but no laughing yet.

So, how old was your LO when he/she started laughing and what did you do to elicit those adorable giggles?