Sony has patented a means whereby you can play PS2 games on a PS3. And they're some kooky means.
Rather than releasing (or, well, re-releasing) a new model of the PS3 that's PS2-compatible, or a firmware update allowing PS2 games to run on all PS3s, or porting PS2 games to the PlayStation Network so they can be downloaded, Sony is thinking that maybe a disc-less PS2 that you plug into your PS3 might be the answer.
That's what this patent suggests at any rate, showing a small box that's essentially a PS2 sans the disc drive (it contains a CPU, memory, GPU and RAM), which you plug into your PS3. When the two are connected, you put a PS2 game in your PS3 and the box lets you run the game.
It's messy, tricky and will cost money, but for those who absolutely must play PS2 games - and lack the will or means to leave their older console plugged in - it mightn't be such a bad idea.
Note though that this is just a patent. Companies patent crazy ideas all the time, and it in no way suggests that this is something that will turn up in the marketplace one day.
Those not up to speed on PlayStation backwards compatibility, know that Sony's initial run of PlayStation 3 consoles included the ability for the machines to play PS2 games, a feature that was later - and controversially - removed.
Sony's PS2 adaptor patent explored [DigitalFoundry]