A short commercial for an upcoming Order of the Phoenix preview was recently aired on ABC Family. Thanks to reader Ashley, we have a detailed description of the preview's ad:

The first thing that you see is two (what appear to be) Death Eaters, one with a blue mask and one with a green mask, I believe. It then switches to a scene with Harry in it looking scared and sweaty. Then it switches to a scene with Harry, Hermione, Ron, Ginny, Neville, and Luna riding broomsticks (they ride on Thestrals in the book) in London right over the Thames River. You see the London Bridge in the background and you see a cruise tour boat that they are flying past. Then it switches to Harry, Ron, and Hermione (Ron isn't present in the book) in the Forbidden Forest backing away from something - it's either Grawp or the Centaurs. Then it switches to Harry, Hermione, Ron, Luna, Neville, and Ginny flying past the Houses of Parliament/Big Ben. And then it switches to Harry flying towards the screen with London in the background, over the Thames River.

The Order of the Phoenix preview will come as part of ABC Family's Harry Potter weekend, which will air on December 1st. We will have a video online shortly afterwards.