This takes some technique and time to achieve the amazing results seen here but it can be done. The link/source has the instructions. Win.
Upside down table for a toddler bed or dog bed - very smart! I would add some very short legs underneath just so it isn't sitting right on the ground.
We're going to do something very similar to this in between our raised beds to grow pea plants on this summer. It will be like a living tunnel for the kids to play in.