As you can see from the image at right, this event has something to do with education. Given that Apple is a tech company, we're likely looking at some type of digital textbook announcement.
But I don't know what that could be. Here's what the NYTimes Bits blog had to say:
The event will showcase a new push by Apple into the digital textbook business, but will not feature any new devices, according to a person close to the company who did not want to be identified talking about it before it occurred.
The thing is, I don't see how Apple plans to make a buck if they enter the digital textbook market. This isn't a market that is primed for growth (like ebooks). On the primary and secondary school levels textbook purchases are dependent on taxes, which is a finite supply as well as down this year in most places. And on the college level, students are buying fewer textbooks each year.
Then again, maybe Apple knows something I don't. Maybe they're not in this for the direct profit. On the other hand, they might have pulled off some amazing technology that they want to show off. We'll have to wait and see.