From Hip To Knit:

Don’t be caught without this hat. It’s basic, head-hugging, and easily adapted to endless possibilities. The hat shown is knitted in stockinette stitch, but you can knit the edges and/or other areas in garter or seed stitch. Or use this solid-colored base as your palette and embroider freely. Work as many colors as you dare into one hat with a rainbow of stripes. Or detail it with only a soft roll at the edge and subtle lines created by shaping the crown, and your hat can become as individual as your head.