At one point, some years ago, every time I went into a yarn store I would buy a skein of Manos del Uruguay's Wool Clasica. Sorting through my vast holdings, I've discovered that I have quite a bit of it. . . I have sorted it into a couple of blankets and a sweater (and maybe a second sweater), but there are still some skeins that don't go anywhere in particular. I looked for a hat pattern that would take just one skein, and found one that works -- I knit it up today to make sure there was enough yarn.
The pattern is the Basic Men's Toque, and you can download it free via Ravelry.
I knit 7 inches, not 6, before the crown shaping, and still had quite a bit left over. Next time I may knit some extra inches to make a fold-up brim, although I do like the way this pattern has you work the first two inches with a smaller needle, providing some subtle shaping.
This hasn't been washed or blocked (although it is a lumpy bumpy yarn so will probably look much the same), and it definitely looks better on a person than laid flat. It's a fine project for a car ride or an outdoor concert or when instant gratification is needed.