The anniversary of Operation Market Garden (the operation whose failure ended the Allies "Home By Christmas" hopes for World War II) is tomorrow, and with it comes the opportunity for an achievement for those that own Brothers in Arms: Hell's Highway
. There are three different versions of the game with the achievement, so there is the possibility of 150GS for those that own all three versions.
Unlike a lot of the other calender reminders, this is rather unique in that you must be connected to Xbox Live to unlock this achievement, meaning you can't just change the date offline to obtain it. You can, however, change the time zone to either get the achievement earlier than tomorrow or, if you left it late, obtain it for a short while on the 18th September. Of course, how much you'll benefit depends on what time zone you're in. No matter where you are, just remember to earn it at some point soon, or you'll have to wait another year before you're able to get it again.