That looks like a lot of fun, OP! When I was a kid, my cousin had a Sit-N-Spin ....same idea, but it was made of cheesy plastic. I LOVED that thing! I wish I had one now! (I'll take the metal one in the pic....steel is real!)

As adults, our only real option is to get a zero-turn mower.... After mowing the grass, you can just spin around in circles for a while and go "WEEEeeee!!!!!". (I'm actually in the market for a zero-turn....seriously!)

EDIT: What my cuz had musta been called something else...I just looked up Sit-N-Spin, and it wasn't it!

Edit #2: Ha! Found it!- like this!: