Click to viewThe countdown clock over at has ended, revealing a rather cryptic teaser trailer entitled "Keep It Clean." It depicts a large, futuristic looking city being destroyed and ends with a flash of the Halo 3 logo and the words "Prepare to Drop". The folks here at Kotaku are combing over the video and website to discover what exactly the teaser means, and will keep you updated as more information "drops." Hit the jump for the full teaser trailer!