Take a look at the first photo attached to this message folks. You most likely have one of these stuck on the outside of your house somewhere. It is a shutoff valve and backflow preventer for lawn sprinklers. Even if the valve is currently shutoff to your sprinklers, the part of these pipes BEFORE the valve is still full of water and can freeze tonight. Since you will not be able to go buy anything from the store today to protect it, find an old blanket or a couple of bath towels and wrap the pipes as best you can, in as many layers as you can. Then finish it with a kitchen garbage bag (as seen in the second photo) to keep the whole thing dry, secured with string or wire of some sort. This should protect those exposed pipes just fine for you.
Another trick that I learned as a kid in Colorado was on really cold nights, just before going to bed, we would open EVERY faucet in the house slightly until they are barely dripping water. Open BOTH the hot and cold sides of the faucet as well, because oddly enough hot water pipes typically freeze inside walls long before cold pipes do. By allowing the faucets to slightly drip this keeps the water slowly moving in those pipes inside your walls, and is often enough to prevent any freeze damage. If you do this, don't forget any laundry sinks you may have in your garage. In my opinion, it is well worth wasting a few gallons of water overnight in order to prevent an expensive plumbing repair. During the day they can all be closed again, because normal faucet use in an occupied house will usually suffice to keep the water moving in your pipes.
I hope this information helps someone out. Good luck to all! Stay safe and warm, and enjoy this beautiful treat while it lasts.