No, not something with which you can fall down faster, we're talking about a Physics Processing Unit, as in "GPU", which is what they're calling 3D accelerators these days.
Jeff left a comment about the Epic guys being just down the road from him, and while searching on "Epic Tim" to check the spelling of "Sweeney", I came across an interview he did with Gamespot about the Ageia physics accelerator (PhysX).
It sounds cool. UT aside, Max Payne 2 really showed off a software physics engine, but there were places in which you just wished for more. More realism. Some Soldier of Fortune-level interactivity (if you get my meaning)...
Idle speculation warning. I have no idea how these things work. As someone that relies on other smarter people around him to do mathematics, I likely never will. But it's fun to speculate.
So, the thought that sprang to mind is: will this end up as part of a GPU? If not, why not? They seem like a pretty close match for each other. I wonder if a GPU couldn't be specialized into doing PPU things (and if we won't end up there eventually anyway). Then, all we need is audio (my money was on SoundStorm 2 being integrated with GeForce 7 before Nvidia said they would put it back into late model motherboards) added back onto the video card (like the good old days of NV1), and we have a cookin' total gamer upgrade package for one low, low price. Hopefully.