Whoa! That's insane! Hopefully the great success that Call of Duty 4's Variety Map Pack enjoyed will mean that the next map pack will be released even sooner. Shame Halo 3 hasn't had as much luck with its Legendary Map Pack, I was tempted to download that today but hardly anyone on my Friends List has it.
On a sidenote: I've started to really enjoy playing on Creek - it's now one of my favourite maps! After Broadcast, of course!
Still, three cheers for Infinity Ward!