I came across this amazing little roller coaster video hand built by a loving father for his kid to zoom around the backyard. Not only is this one of the coolest toys I’ve seen in a backyard it is also very eco friendly. A push powered coaster you could say.
Have a look at the video and get creative in your own backyard. I’ve been pondering the idea of building a skate ramp for my son. If I can drum up enough used materials over the next few years I will take on the task.
A greenhouse is another idea I’ve been thinking about. This can be done easily with waste materials such as recycled bottles and windows. Here is a good link from treehugger.com on how to approach this task.