Pattern includes instructions for working a hat in any size, any gauge, and tips for mixing yarns.

It’s very rare that the final stitches of any project use up the final yards of yarn. More often, you have anywhere from several yards to most of a ball left over. It’s never quite enough for another project, but it pains many knitters to throw it out. So what do you do with it?
The Women’s Spirituality Group of Grace Church in Amherst, Massachusetts, came up with a solution. Whenever someone finished a knitting project, she would toss her leftover yarn into a bin that was kept at the church. Anyone was welcome to sift through the bin for yarn, pulling out combinations of textures and colors that pleased her. The knitters made hats with the odds and ends and sold them at the annual St. Nicholas fair. The fair opened at 9:00 a.m., and the hats were usually sold out by 10:00. All proceeds went to the church.
This system could easily be replicated by any knitting group. Sell the hats, donate them to a local shelter, or keep them and wear them!