Debbie Stoller's All Day Beret.
This was a great pattern I made awhile back - one of my first projects worked in the round. I lined the inner edge of the hat with fleece to keep it cozy and warm.
Unfortunately, I was using a ball of leftover yarn that looked promising but didn't necessarily meet the pattern requirement. As I worked along, it became pretty clear that I wouldn't have enough yarn to complete the entire chart, so I decreased sooner than the pattern suggests. This made the hat lose the droopy beret effect, but I think it still turned out well! It fits great - the ribbing makes it very flexible - and I really like the diagonal look.