Many of us remember back in 2006 when Peter Jackson, the director behind The Lord of the Rings Trilogy and Bad Taste, said that he was working on bringing Halo to the big screen. Unfortunately, that attempt didn't pan out. That same year (specifically in September 2006), he also announced an episodic Xbox 360 game that his Wingnut Interactive studios were developing with Microsoft Game Studios, entitled, Halo Chronicles.
Last Friday at Comic-Con, after showing off District 9 (a film he produced, and directed by Neill Blomkamp who was slated to direct the Halo movie), he told Joystiq,
"That Halo project is no longer happening, it sort of collapsed when the movie didn't end up happening."
Which is a bit odd, considering there were confirmed reports as recently as April 2008 stating,
"Microsoft Game Studios has been hard at work collaborating with Peter Jackson and Bungie on the development of [a Peter Jackson-helmed Halo project]." - Microsoft
Even last August, 343 Industries (The new Microsoft "Halo" studio) hired Ryan Payton (producer on Metal Gear Solid 4), who was confirmed to be working on the project.
So perhaps a game is still in development, but it just won't be headed by Peter Jackson and crew. That's all right though, he's got enough on his plate, what with The Lovely Bones, Tintin and The Hobbit films, just to name a few.