Easiest solution will depend on exactly where your antenna is going and what you have available. All buildings have a ground rod. Some use the reinforcing bars in the concrete of the foundation, some use a copper rod driving into the earth, some use metallic water pipes leading back to the street, some even use a combination of all of them.
If your antenna is going near your electric meter panel, there should be a ground connection there. In my home, the steel rebar from the foundation/garage slab poke up through the concrete. This would be a good option, if you antenna was being mounted nearby.
Other option is to drive a new ground rod as close to the base of your antenna as possible. Hardware stores will have 6 or 8 foot ground rods in their electrical department, as well as the clamps used to attach the wire to it. Basically you need to drive that ground rod into the earth. Make sure there is nothing below the ground you are going to hit, though.
National Electric Code says that all your grounds need to be connected together, do this.
What you are doing is giving any energy that isn't supposed to be there an easy and quick way to get to ground. A direct lightning strike, induced energy from a nearby strike, fallen power line, or just static electricity from the wind/weather all need to get to ground rather than going through your radio. If you don't provide a proper ground, static, induced energy or a direct strike can and will find a way to ground, either through the soft bits inside your radio, or worse, you. Giving the energy and easier way to get to ground can protect you, your home and your radio.
Keep in mind, though, that it's nearly impossible to protect all your gear from a direct lightning strike. Due to the high voltages and amperages, not much will stop it. Remember that energy traveled hundreds or thousands of feet through the air. A few pieces of plastic or rubber isn't going to stop it.