The so-hot-right-now zombie-fleeing ArmA II mod DayZ has now been played by over one million people.
At time of writing, the four-month old mod now reports 1,006,566 unique players. This time last week the count was at 934,160 - that's 72,406 new players in seven days, which is probably bigger than the entire UK games market right now.
While DayZ creator Dean "Rocket" Hall investigates the possibility of a standalone version, the alpha version of DayZ is free but requires a copy of ArmA II: Combined Operations (the original game plus its expansion pack Operation Arrowhead).
Right now VG forumite extraordinaire Mr_Ninjutsu is keeping a diary of his DayZ adventures.