Here's a madcap way to celebrate your little one's growing delight with unexpected events.

Appropriate for: 4 to 10 months
Skills developed: Visual, sense of cause and effect
What you'll need: A wide-ranging selection of odd items to put on your head

In the classic children's book Jenny's Hat, a little girl who's disappointed in the hat she receives as a gift tries on all sorts of odd things (a lampshade, a flowerpot, an old-fashioned TV antenna) to see if they make better headgear.

Taking inspiration from Jenny's experiments, pretend your house is a hat store and round up a number of possible toppers. Nothing cracks a baby up like the sight of you wearing a tea cozy on your head. A cardboard box, a plastic bowl, a pair of shorts or leggings, or a wicker basket can also do the trick. As you put each object on your head, make a perplexed face at your baby and ask (à la Dr. Seuss), "Do you like my hat?" For a real capper, sit your older baby in front of a mirror and put the silly hats on your baby's head.