In 2005, I learned how to knit hats on knitting looms in elementary school knitting club. I taught a few friends on my swim team how to knit hats, and we would knit them at swim meets while waiting around between races. We sold the hats annually as a fundraiser for our swim team for five years.
We made several sizes of hats, including baby hats, hats for kids, and hats for adults. Sometimes we would also also knit scarves or straw-weave scarves to sell. Each year, we would make about 50 hats. After selling the hats at the annual fall swim meet, we gave 100% of the profits to the team.
I came up with several designs by changing yarn color while knitting, such as a "Davis" team design, a butterfly pattern, and a smiley face. I also came up with a jack-o-lantern design that I made by embroidering the face onto the pumpkin after knitting, and a watermelon design that I made by adding embroidered seeds on that hat after I knit it with lots of striped hats, including customized team color hats that were ordered.