What is it? Who knows? That's why the verb "tease" was used in the headline. "Get your rooster hats ready! We have a very special announcement coming very soon ..." says the page. DSiWare? iPhone? Pure conjecture.
Also, this seems like as good a place as any to mention this. Reader Soniking points out that if you write "teleporter" in the game, you're taken to a Scribblenauts version of the 5th Cell development studio. Maybe there you can find out what this announcement's about! Facebook: Scribblenauts [Facebook, via Joystiq]