Ages: 6 Months and Up

The best things in life really are free. And when it comes to playthings, you can't beat a cardboard box. Lenore Grubinger, a developmental specialist from Northampton, Massachusetts, suggests turning one into a tunnel for a pint-size version of full-body peekaboo (an activity that lets your baby practice leaving and coming back to you, a skill he'll need for walking later on). To make one, first find a large box and be sure there aren't any staples poking out. Cut off at least three of the flaps on opposite ends of the box, leaving 3 or so inches on the right and left sides to help support the structure, as shown above. Decorate it if you like (we used a little colored electrical tape). Now put your child's favorite toy inside to get her attention and let her practice scooting in and out of it.

For added fun: Tape a fabric curtain over one or both ends of the box so your little crawler can really make a grand entrance.

In addition to boxes, your house is full of playthings and other objects that get kids moving. Consider these fun ways to play with some of them: