It's that time of year, the time when everyone is out and about, braving the crowded stores and getting prepared for the holidays. It's crazy-busy, and exhausting, and if you live on the flight path between your friends and the local shopping center, you will probably get some spontaneous drop-in visitors in search of a restorative cup of tea, a supportive hug, and a rest room with no waiting line. Even if you didn't get more than a quick text message saying, "I'm coming over in a few minutes", you can throw together a cake that's sure to cure the shopping blues. This last-minute from-the-pantry chocolate gingerbread cake comes together in less time than it takes to preheat the oven, and in an hour, start-to-finish, it's baked and cooled and ready for visitors. Even better, if you have a few minutes at the end of the day, throw one of these cakes in the oven. When it's cooled, cut it into four pieces and freeze. Each piece will serve 3-4 tired friends. Dust the cake with powdered sugar, or top it with ice cream, right before serving.