This is awkward.
I came up with a premise that I think could make a good story for NaNoWriMo 2009, but it's only June! I have to put this on ice for another 4 1/2 months. The most I should let myself do is come up with an outline for the overall story before the month starts.
I used an outline for my NaNo story last year, and it worked out pretty well for me. Really, the only chapter that I wrote out of order was the very first chapter. Everything else fell into place, regardless of how much I abandoned the "robbing a store" scene.