The first time I can remember Ian actually giggling was during his first year. He was sitting in his baby-bouncer, and for some reason I started rubbing the top of my head against his stomach. And he giggled. It wasn’t the squeal of delight so common to babies, or that high-pitched, Tim Allenish grunt that means your child is either happy or bloated. It was a full-fledged giggle.

So I did it again. And again. (Parenting isn’t so much about raising a child as it is a series of psychological experiments.) Soon the giggle turned into one of those spasm-like, silent laughs, when your lungs are ready to burst and you want to breathe but you can’t because everything is just so darn funny and won’t someone please make it stop!

Two years later, and Ian hasn’t stopped laughing. I’ve never seen a happier (or more easily amused) kid. Last night we took him to Burger King, which had a play-area. Soon after, another toddler arrived, who was about six months older than Ian. This kid could run circles around Spider-Man. As he raced through the gauntlet of rope ladder/crawl tube/slide, he passed Ian again and again and again, and each time Ian had an apoplectic fit of laughter. Whenever the two would meet at a corner, or glance at each other through the netting, Ian would squeal and laugh.

He has the same reaction with cats, and we have three. They can do anything – anything – and Ian will laugh. Walk, jump, lift a paw, blink, inhale…We have a tank of oxygen on hand for those times when they actually play with him.

There’s an episode of Seinfeld where Elaine claps and cheers for a pair of spinning tires in front of an auto shop. Should I fear for my son’s sanity?

Every night I lift Ian to sit on top of a cabinet in our bathroom, so I can brush his teeth. He can just reach the light switch from this position, and if Ian loves anything as much as laughing, it’s switches. Last week he put his hand on the switch, scrunched his shoulders and smiled. We both knew what he’s going to do, it’s not as if he’s being creative or clever…and I laughed when he flipped the switch! I didn’t just laugh – I guffawed! I put my head into his lap and laughed and laughed, every time he flipped that stupid switch. We were both in fits of giggles by the time Kelly came into the bathroom, wanting to know what was so funny.

I have no idea.