About a year ago, I bought some wool dryer balls. Since then, my mother, mother-in-law, sister-in-laws, and sisters have seen them and asked about them. I definitely notice a difference in drying time when I use them. I've thought about getting some for the women in my family, but they can be pretty pricey. However, The Seasoned Homemaker has a tutorial to make your own. I think I just added something else to my list of things to make!
See How to Make Wool Dryer Balls.