If you would decide that you would like to have your tofu available at a later date, or if you decide that you would like to remove some of the moisture from your tofu to help it soak in sauces and flavors, you can freeze it. Freezing tofu is also called "pressing" it. First, take the tofu out of its package and place it on a cutting board to allow the packaging fluids to drain off. This step will help keep too much ice from forming around your tofu when you freeze it.
Next, place the tofu on some paper towels, and cover the top of the tofu with some paper towels as well. Then find some slightly heavy object (like a small book) that can be placed on the tofu's top paper towel layer. The goal here is to find an object that is heavy enough to press down on the tofu and cause its fluid to be pushed out without actually crushing or collapsing the tofu. Leave the object on top of the tofu for 15 minutes.
After 15 minutes, remove the object and all paper towels from the tofu, and place the drained tofu in a freezer bag. Make sure you run your hand over the tofu and bag to remove all the air pockets before sealing the bag. Then just place it in the freezer.
Your tofu should be fine for at least 2-3 months when frozen in this way. When you are ready to use it, just remove and thaw. Some tofus will change color slightly after being frozen (usually to a slightly more yellowish color) and most will also have a slightly different texture (usually a little more "chewy").