Appropriate grades or age groups:
Preschool and Younger
Elementary School
Middle School
High School & Beyond

Estimated time to complete activity:
Few hours a day, for a week or so, then a Weekend.

Materials needed (if applicable):
Things outgrown and no longer cherished

Description of Earth Day activity:
Have a garage/yard sale! There are some Yard Sale Tips listed in What Works, if you check the Topics listings...

Clean those closets, turn trash into treasure.

Other suggestions or comments:
Re-Use is the highest form of recycling there is!

If the weather's not quite right for a sale by Earth Day, you could just launch preparations for a sale later. Do your Spring Cleaning; price, bag and box the items until the day you are ready to set up shop. Celebrate your cleaner home environment with a picnic/pizza party/cookout, or popcorn and video night.