Played about 12 frames' worth of Wii Sports Bowling. Alan Cooper, a UI design consultant that become fairly well-known for his book About Face back in 95, talks about how software UI should conform to a user's "mental model" rather than a programmer's "implementation model". An Atari 2600 joystick has eight easily understood states, and the understanding that it's give or take limited to two players on the screen at once helped ensure many of the first few 2600 games looked very similar to one another. Programming games that match the restrictions of the hardware is, of course, to limit the gamer's experience to the implementation model.
The Wiimote seems to do a very good job conforming to my mental model. Without reading any instructions, I was able to pick up the controller and place some pretty interesting spins on the bowling ball, just as I'd wanted.
The results weren't always even as good as I bowl IRL, but did a great job overall. I'm impressed, and see why the Wii is getting good reviews and having even better sales. If I find $750 lying in the street marked specifically for buying a console, I'd get the Wii at this point and bank the balance for another console later.