Until you start looking for them, You would not believe how many wood pallets are just lying around the street right by your house. These pallets are usually made from strong wood in order to carry heavy weights like construction materials, fruits, goods and basically anything that can come off a truck.
Don't be scared if they look dirty - Sandpaper can clean them fast and easy.
In the following links I will show you the greatest ways the web has to offer for reusing these pallets.
It's Green, Fun, fulfilling and you can make really great, useful things out of it.