Like its predecessor, the Wii U is probably going to rely quite a bit on experiential knowledge. The GamePad controller at the center of the experience is the kind of thing you can't really judge without trying it out. Luckily, now you can, since Wii U demo units are starting to show up in retail stores.
But instead of driving to Wal-Marts and GameStops randomly looking for one, you can use a handy locator set up by Nintendo. Just punch in your zip code and see where you can go to get your hands on one of the systems.
The Wii U ad campaign just kicked off to get people excited for the upcoming console--not that it matters. Pre-orders have already sold out both online and at retail, so trying your luck to get one on launch day is a gamble at best.