I realized that I did not stay at a Starwood Hotel yet this year, so I was considering just booking the cheapest local room I could find for one night (the hotel equivalent of a mileage run). Before doing so, I called SPG, and they looked at my account and said that I have until the end of June 2009 to earn points to not lose the ones I have. I guess that accounts for the six month "inactive" period before you lose your points?
I find the definition of a "stay transaction" confusing (i.e., what is required to maintain your account). An SPG CSR in the past told me that it must be a hotel stay and that a meal would not count, but the very kind Starwood Lurker says otherwise. I'll try a meal at a W in the near future, and plan on staying at a *wood property on my next trip.