This could either fizzle or be huge
It appears as if Nintendo will be "bringing E3 to the public" in the words of Nintendo of America President Reggie Fils-Aime. Nintendo will be bringing playable builds of their newly announced Wii U games to select Best Buy locations (US and Canada) during the week of E3. We don't know any of the games that will be offered so far, but Nintendo will announce more details (presumably location information) the week of June 11th.
This may seem like a minor occurrence, but this is actually pretty huge depending on what titles are going to be offered. E3 is a particularly closed event, so if you don't get in, odds are you aren't playing any build of a newly announced game for months, perhaps even years.
Imagine how crazy local Best Buys would get if there was a playable build of the new Smash Bros. game. Wishful thinking? Yeah, I know, but imagine the on-spot tournaments!