Call of Duty: Black Ops was released a month ago today. In that time, it has already sold more copies in the USA than games like Ocarina of Time, Super Mario Kart and Halo 3.
Looking for specifics? That's 8.4 million copies sold. In just the United States. Of course, it helps that the game was released across Xbox 360, PS3, PC, Wii and DS, but still. It's impressive!
Those numbers don't just put the game ahead of the lifetime American sales of the three titles outlined above, but also those of other classics like Grand Theft Auto III, Tomb Raider and Metal Gear Solid.