Real World Events
- April 25: Volume 2 of the Halo 2: Original Soundtrack was released.
- May 12: The Halo 3 Announcement Trailer was first shown at E3 2006.
- May 17: The discovery of the extrasolar planet HD 69830, which the Kig-Yar homeworld Eayn supposedly orbits, was announced.
- July 19: The Halo Graphic Novel was released.
- September 27: The Halo Wars Announcement Trailer was first shown at the Microsoft X06 media briefing.
- October 31: The novel Halo: Ghosts of Onyx was released.