I think one of the number one places that people get ringworm is from their pets. Its very common in rodents like guinea pigs and also very common in cats. If you don't pay close attention to your pets, then they may have ringworm and may give it to you. I recently thought that my guinea pigs had ringworm and we had to take them in to an exotic vet so that we could find out to make sure that we wouldn't get it. I just thought it would be good to share this advice.
Another main source of it is contact sports like wrestling or basketball. In case that one get's infected though, you can simply use cider vinegar with a bit of water and it usually works get rid of it.
Gyms and the Y is another great place to get ringworm as well. I know I had a case a while back on my leg and the only thing I can think of is one of my dogs rubbed on my shorts before I put them on. [[span class="Apple-tab-span" style="white-space:pre"]]
I got it from my cats when I was a kid. My doctor said I could have also picked it up from playing in the dirt a lot. I liked to make mud pies and just get all dirty out back.
I think Ring Gaurd is the best medicine for remove ringworm. I use its medicine and effective for  ringworm.
Many years ago I got ringworm from my niece. I was babysitting 4 of my sister in laws kids for 2 weeks and the girls slept in my be with me. About 1 week after they had slept in my bed the oldest girl starting getting itchy and I took her to the Dr. He said she had ringworm. I was kind of worried. About one more week went by and I got out of the tub one morning and looked into the mirror. I was covered with ringworm. It took medication that I had to rub all over my body to get rid of it. It was very itchy. I do not think I will let anyone sleep in my bed again.
I knew people got them from cats that go outside, but I never thought about pets that remain inside. I mean seriously, how did the indoor pets get it to begin with? I had no idea ringworm was that common. My mother used to tell us we would get ring and hook worms if we did not wear shoes, but I do not know how true that was.
Already detailed posts on where we can get ringworm, just like to say if we will keep our home and pets clean we won't have ringworm issues.