Portable floor for outdoor basketball?

Factual Questions
1

(Cross-posted from IMHO, thanks to an excellent suggestion by Jake)

My little boys love basketball, but they’re outgrowing their Fisher Price basketball hoop. I want to get them something bigger, but we have no good outdoor space to bounce a ball. Our driveway’s at the top of a hill, so it’s no good–the ball’s going to roll into the street. We have no patio, and our deck won’t work because (1) there are glass windows and doors, and (2) they’ll have to run up and down the stairs every time the ball goes over.

I was thinking about pressure-treated plywood, but I don’t know that it’s strong enough to support them running around, especially since it will have to be laid over grass, and I hoping for something I can take apart or roll up or something, so it’s only down on the grass when they’re using it…

Anyone have an idea? My 4 year old will be 5 in June, and he’d really love it.

2

IMHO, what you are asking for just can’t really be done. It’s the temporary thing basically, I suppose you can put one sheet of plywood (no real need for pressure treated here) or OSB down on a flat and level piece of grass but if you want a bigger court it gets really difficult and would have to be semi-permanent.
It’s probably easier to park you car sideways at the end of your driveway or better yet, use said plywood to build a barrier to stop the ball from going into the street.