Ready, set, crawl
How to play: Use cushions, sheets, blankets, and doormats to make a variety of tunnels and bumps for your baby to crawl under and over.

Why babies love it: When an ordinary room becomes a veritable playground, the opportunity for fun seems endless. (And trust us: The photo ops will be worth every minute of cleanup time.)

What it teaches: Motivation. Once your baby gets into the maze of tunnels and hills, she'll be so curious about how she got in  -- and how to find her way out  -- that she'll draw on many of her newly learned physical and cognitive skills to help. "This kind of integration of different skills shows a child that she can rely on herself to find the answers," says Claire Lerner, director of parenting resources for Zero to Three, a nonprofit organization.

When to start playing: 8 months and up, when she has the motor skills to crawl and pull herself up.

Beyond peekaboo
How to play: Hold a burp cloth in front of your face and ask "Where's Mommy?" but don't pull the cloth away yourself. Wait for your baby to do it. When he reaches for it and sees you, say "Here's Mommy!"

Why babies love it: "Finding" you  -- someone your baby knows and loves  -- is a sweet surprise every time (and we mean every time: This is not a game he'll let you play just once!). The funny face you'll probably make when your baby pulls away the cloth ups the thrill factor, and he'll imitate you.]

What it teaches: Manipulation skills. (Don't worry: not in a conniving, you'd-better-watch-out-later-on kind of way.) This game helps him understand that when he behaves a certain way, people will do specific things, like pick him up if he cries or smile back if he coos. He learns that by removing the cloth, he can control what he sees.

When to start playing: 6 to 9 months, when your baby has the motor skills to reach for the cloth.

Meghan Rabbitt also writes for Prevention, Shape, and Family Circle.