My first grandchild, whom we babysit every weekday, is eight months old, which is a tremendously fun age. She crawls, she's taking her first wobbly steps...but the best part is, she's now old enough to participate in game-playing.
Lots of things amuse her. We put her in one of those little playpens that are full of featherweight plastic balls, and my daughter threw them up so they'd come raining down all over the place, and the baby thought it was hilarious! The other day she had her first "pillow fight" as her daddy held her and I tossed small pillows at her tummy. Same thing, she cracked up. I held one of her little dolls by the head and wiggled it so the feet wobbled back and forth in a dancing motion, and she was just in hysterics.
It's not just that a baby's laugh is so cute -- which it definitely is -- but it's highly infectious. We all bust up laughing watching her laugh. Honest to God, I've had tears coming out of my eyes watching her giggle hysterically, and my cheeks hurt for minutes afterward from laughing so hard with her. It's one of the best natural highs in the world. I just adore my little granddaughter.