Homespun Hearth is doing one as well.
http://www.homespunhearth.com/detail...uper-Bowl-2018
You have to sign up, but it's free. I like that they tell you that the dark and medium fabrics should be shades of the same colour (dark and medium blue, red and pink, etc). This gives me more of a feeling of control over the final product than I get with most mysteries.