You can view the site here. When I visited around midnight, the site appeared to be in a broken state.
According to My Game Flash, the working version of the page is titled "Something is Happening in the Sky." The page shows an air ship on fire and slowly descending. People can occasionally be seen gliding down on parachutes, having apparently escaped from the ship.
From the background music to the character designs and color scheme, the page has a comical sense to it. Whatever game this turns out to be, it will probably be something light-hearted.
Whenever there's a countdown or teaser site, you can always count on someone to check the source code or flash script for hints at the game's identity. Some visitors did just that for this title and found an HTML meta tag listing PSP as the hardware.
That's not a guaranteed indicator of platform, of course. But thankfully, the wait for proper details won't be too long, as the page promises an unveiling -- or cutting down, rather -- on the 19th. That's a Thursday, which usually means a Famitsu unveil.