I like to approach the entire month of April as the Earth Day Season. Every year, I offer my students the Extra Credit Recycling Challenge, inspired by
ReadyMade magazine's MacGyver Challenge column, wherein readers are challenged each month to create something great using an item destined for the dumpster. In return I get all kinds of crafty cardboard box cabinets and tin can pencil cups through which students learned about creativity and conservation. The latter is a required learning objective; the former is a bonus!
So, in the spirit of Earth Month, here are some of my favorite re-use projects from here and there.

Learn how to sew juice pouches into a pencil bag with
Skip to My Lou's
tutorial.

Or, if you have a lot of juice pouches, visit
Thrifty Fun to get instructions for making this
tote bag.

For a different take on the recycled pencil holder, check out
Craftzine's cereal box
pencil case tutorial.

Perhaps most appropriate for this time of year when school is ending and supplies have been all used up is this
jump rope made of dried up markers. Visit
Mommy on a Shoestring for the complete tutorial.
Images from Skip to My Lou, Thrifty Fun, Craftzine,
Mommy on a Shoestring.