2. Collect runoff. Have your preschooler place watering cans or buckets under the downspouts of your house. After a storm, she'll be thrilled to see that her cans are full, and she can use the rainwater to give houseplants a drink.
3. Jump on it. "I lay milk jugs, aluminum cans, and boxes on the floor and let my son stomp on them to make them flat for recycling," says Dalia Stein of Columbus, Ohio. "He fulfills his little-boy need to destroy things while doing something nice for the environment."
4. Put your kids in charge of reminding you to switch off the lights when you leave a room. They can even pretend to issue you a ticket for infractions -- and they'll be less likely to waste energy themselves.
5. Head outside. Gather apples or pumpkins at a pick-it-yourself farm. Seeing where the food comes from helps kids grasp why it's important to care for the earth. Plus, you'll be buying local produce -- saving the energy and packaging used to ship food long-distance. Go to pickyourown.org
6. Play with trash. Turn a neighborhood cleanup into a scavenger hunt. Create lists with pictures of plastic bottles, soda cans, and paper trash. Have your kids go hunting, and then recycle what they've found. (Just be sure everyone wears gloves!) Whoever finds the most items wins a prize -- say, any money you get back when you recycle the bottles and cans.
7. Build a toy lab instead of a bear. Throw your junk -- empty juice boxes, broken Barbie legs -- into a box along with glue, tape, and string so kids can create new toys and avant-garde art. Need ideas? Check out kinderart.com/recycle
8. Power down. Once in a while, have a No Electricity Day. Shelve the PlayStation, shut off the TV, and use only toys and games that don't have a plug or require batteries. You'll save energy, and your child may find he prefers Crazy Eights to another viewing of Cars.
9. Organize a kids' clothing swap. Haul out outgrown jeans and sweaters and get together with a few mom friends to trade. You take home new-to-you clothes that fit your child now, which is healthier for the planet -- and your wallet -- than buying brand-new duds. Have a toy swap, too.
10. Spin an eco-tune. "We love the song on the Curious George soundtrack called 'The 3 R's,' for reduce, reuse, and recycle," says Kristi Walsh, a mom of three in Chelmsford, Massachusetts. "My kids sing it when we take the recyclables out or when they're washing their hands together to save water. It reminds them that even the simplest job can help the environment."