Microsoft and Bungie's Halo 3: ODST has sold approximately 2.5 million units in the two weeks since release.
That's according to a report by USA Today, which notes that the game has generated USD 125 million in sales for the 27 million unit-selling franchise.
The report also points out that Microsoft's 343 Industries division, which handles all things Halo, is also working on new game Halo: Reach, a second Marvel comic book series set for release before the end of the year, the Halo Legends anime to be shown on the Halo Waypoint Xbox Live channel, and more books and figures from McFarlane Toys.