This lesson utilizes leaves to practice finding the area of an irregular shape using previous knowledge of polygons. This lesson can be adapted for many levels of math by changing the requirements to suit individual classes/needs.
This lesson is perfect for a nice fall day! I usually would use this lesson after learning about area or as a pre-activity to a unit to informally assess students. It lends itself nicely to the beginning of the year when you are still getting to know your students. At the end of the project I usually cut out all of the leaves and paste them on a class tree. This will also brighten up your classroom and display class work for parent teacher conferences.
zip file with word doc/pdf of lesson and .jpg of finished example.