Where did these lady bugs come from???

When we got home from church today, to our surprise our house was COVERED in lady bugs! They are everywhere, and we have no idea why. Is this their season? Whatever is going on it is wild! I took some pictures, but you may not be able to see them and it does not do them justice. They are even getting in the house. I had one crawling through my hair, and all I did was walk from the car to the house. You can walk to the west side of the house and it looks like a bunch of little butterflies just invading the area, you can't even walk through without them landing all over you....uhh, gives me the willies. Not that I am afraid of lady bugs, I just don't like what it feels like to have bugs crawling on me!