Two things worth highlighting:
1) For a printable version of the information in this thread, download this pdf from google docs. It's not small so it may take a bit to load. It'll print in higher quality if you download it to your hard drive and print it locally. The full document is 51 pages long. (If that opens to a blank window, choose File => Download from the page's File menu.)
2) For a list of all pack sales and double bonus point sales since this thread was created see this post. Knowing when the previous sales happened will help with predicting when the next one will be.