Call it a hunch, but the giant orange 5 that's popped up at armoredcore.net/ac5/ might have something to do with From Software's reveal of Armored Core 5.
Whatever the case may be, we'll know in three days. January 14th is the date listed under the large, glowing 5, with the word "BEGINNING" suggesting that From plans on revealing the game in stages. Or perhaps the company just enjoys being mysterious. It isn't doing a particularly good job of it, but we'll give them points for trying.
I'd be extremely excited about the Armored Core 5, if it weren't for Armored Core 4.
The Armored Core 5 Teaser [From Software - Thanks Zippi!]