First, a Ravenclaw hat using double-knit to put some words along the brim.
It reads, "Wit beyond measure . . ." I'm utterly in love with double-knit, especially on hats. Double thickness over the ears, AND I could put in words.
The second hat is a little more subtle. It's a Fair Isle hat with the Deathly Hallows symbol worked into it. So far, nobody I've polled has noticed it without having it pointed out, but it still makes me happy.
I even put circles, lines, and triangles up along the crown, right before the decreases. The hidden iconography makes me happy--it seems appropriate for something as vaguely cult-ish/conspiratorial as the Deathly Hallows.
EDIT: By request, here are the charts for both hats. I may eventually write out the whole pattern for the Deathly Hallows hat, but for now, you can have the chart.
Wit beyond measure chart, worked on 85 stitches
Deathly Hallows chart worked on a multiple of 18 stitches.