DiscoStu - 8:31 pm on Jun 23, 2010 (gmt 0)
So I just realized it was already activated in my account, not sure for how long. If you applied, go to campaign settings and scroll down and you should see it down at the bottom.
Still trying to figure out, but for now it seems you can only test at the adgroup or keyword level? That is, I don't think there is a way to test different bidding strategies, day parting options, automatic matching etc against each other on the same campaign which is a little disappointing...or am I missing something?