There must be something extra special about September 10th this year.
I've seen hints that Apple will reveal new products, mainly but not limited to iPhone and iPad. Also, Olympus has new products to show on the same day. There have been quick bits about other companies, as well.
Olympus should have at least their new micro Four-Thirds camera body, E-M1, and a new lens for it, a 12-40mm f/2.8 at the high end. (Don't be surprised if Panasonic counters quickly with a GH5, which could be available before the end of the year--in very limited quantities.)
Apple, of course, is nearing the end of their annual sale for students. That means it's time for new models. Obviously, iPad, iPhone, iPod touch, and MacBook Pro models will be revised. You should also expect that iOS version 7 and Mac OS X 10.8.5 will be available that day. OS X Mavericks may be available but I'd be afraid to install it so soon. I'm still waiting for Apple to fix 10.8.4 and iOS 6.1.3.
Will the Mac Pro be available? Who knows? I've heard zero from anyone.
I'm expecting a surprise that has not been mentioned, although I'm not sure it will be shown so soon but certainly before the end of the year. It should be available within the holiday shopping season. (No, no, it's not the Nintendo 2DS! That's interesting, but not exactly shocking.)
Update 2013.09.10: Olympus E-M1 and 12-40mm f/2.8 lens announced. iPhone 5s and 5c announced. It was a slow day.