Ever since Malcolm figured how to sit unsupported (and decided that playing with toys while sitting beat laying on his back under the Baby Einstein playmat of his younger days), we've been trying to figure out a safe way for him to sit and play, but not bash his brains out on our hardwood floors.
The first solution was a combination Boppy/quilt construction (the Boppy being a Top Ten baby item in this house).

It worked reasonably well, but had several drawbacks. First, it was an ugly combination. Next, the Boppy has a place-it-is-supposed-to-be-at-all-times and that's the bedroom, not the great room floor. Few things are more irritating than needing the Boppy at 4 a.m. only to realize it isn't where it's supposed to be. And lastly, the Boppy/quilt combo wasn't really big enough to allow Malcolm to do anything other that just sit. And if he's going to learn to crawl, he needs to be able to flop over, roll around and play on his tummy.

So, the solution came as an (unreasonably) large foam mat, found and purchased on the glorious internet...where anything you can dream of, you can find.