It ends today in Atlanta, as I asked the manager, thinking about buying another MBP as a gift.
I'm pretty sure they just say that to make you buy one, especially if they know you're considering buying and not just browsing.
Same thing when sales say "Limit _ per customer." They want you to think the sale is really good, so you'll buy more then just 1 item, since there's a "limit." Obviously there are some exceptions to this, such as Black Friday, when stores lose money on most of the super good deals. In most cases though, they'd rather you buy more.
But about the Microcenter sale, I doubt it will end this week after they've had it for months. I guess you never know, it's just unlikely.