For millions of video game players, Christmas arrives this morning as they get to unwrap what's expected to be the biggest release of the year, Call of Duty: Modern Warfare 2.

Across the country, fans stayed up late Monday night to secure the action-shooting sequel to 2007's Call of Duty 4: Modern Warfare during midnight sales events at game stores and big retailers including Best Buy and Walmart.

With millions of copies expected to be sold today alone, the arrival of MW2 (Xbox 360, PS3 and PCs; rated M for ages 17-up, $60 and up) is enough to spawn a holiday of its own. "If I were a boss, I wouldn't bat an eyebrow if suddenly the incidence of sick days went up," says Scott Steinberg of DigitalTrends.com.

Publisher Activision has run a series of movie-quality trailers on prime-time TV in hopes of generating the biggest launch of any entertainment property. "It's going to be monstrous," says John Davison of GamePro Media.

The fastest seller globally to date, Grand Theft Auto IV, brought in $310 million on its first day more than top book Harry Potter and the Deathly Hallows (2007) sold in its first day worldwide ($220 million) and $500 million in the first week, more than top film Harry Potter and the Half-Blood Prince (2009) took in its opening five days worldwide ($394 billion).