Rovio, the makers of Angry Birds, is reporting 6.5 millions downloads of the game on Christmas Day, which is just about the same number of total smartphone activations that day.

The total stretches across three games—Angry Birds, Angry Birds Seasons, and Angry Birds Rio—but when you consider the holiday haul is an increase from 2 million downloads on Christmas 2010 and roughly half a billion people already have the game, the numbers are mind-boggling.

No wonder then that Rovio’s IPO could hit $10 billion.

[via Joystiq]