Bungie Studios has reported that more than 500 million games of Halo 2 have been played online since the game launched in November 2004.
In a post on the studio's website, Bungie bigwig Frankie O'Connor wrote: "We've surpassed lots of cool numbers in the past, including numbers of total players, hours played and all that stuff, but we thought we'd note that at as of around noon today, a half-billion games of Halo 2 have been played on Xbox Live. That's a lot of games.
"To clarify - that's actual games, not player-sessions," O'Connor continued.
"That also doesn't include games we lost because the website was down, or through other technical issues. Again, this proves that my scheme to attach Halo 2 sessions to my Paypal account would have been genius."
But will Halo 3 prove as popular when it arrives on Xbox 360 next year? Well, yes, most probably.