From their Facebook Page:

You can't buy happiness, but you can buy cheesecake - and that's kind of the same thing. Share our happiness on ‪#‎NationalCheesecakeDay‬ with ANY slice half price on 7/30!

From my email:

Let the Countdown Begin! National Cheesecake Day, our favorite holiday, is coming up on July 30th. Mark your calendars and be sure to stop by any one of our Cheesecake Factory restaurants to get any slice for half price* in celebration of National Cheesecake Day!

*Offer valid July 30, 2013. For dine-in only. One slice per guest. Must be present.

No Coupon Needed.