And here is my latest, and greatest idea! (okay, maybe not great, but it is new)

Rollerblade Track

Its a layout for a rollerblade track in my backyard. My backyard is huge. I'm always thinking of ways to fill it up. This is my newest one. If you can't figure it out from the simplistic depiction, the idea is to make a smooth track out of sidewalk blocks. My parents bought some of these recently, and since they knew the pricing (~ $5 a block (30" square)) I used that for my design.

The only thing I'm not sure about is the four curved 'corners'. Obviously a square block is not going to easily accomodate my design for roundness. I still need to figure that part out. Oh, and whether I can stay on a track that's 2-1/2 feet wide, especially in the corners.