It's called PolarKnit, which I purchased at The Loopy Ewe. Such a fun place to shop - they have an incredible, unusual selection of all things yarny.
It's such a cool yarn - very thick and knits up super fast. Here's the start of Sam's hat:
I started it this morning using size 10 needles (I cast-on with size 11s) and knitted for maybe 1/2 hour to get to this point.
The colorway is Mermaid; each ball is about 55 yards or so and it's made of 100% polyester fleece. I'm guessing I'll use three balls for this project. It's so much fun to work with and best of all, will be wonderfully warm this winter for Sam.
I'm adding onto this post this evening to say the hat is FINISHED! Talk about a fast knit. Here's Sam modeling his new hat:
Cute, isn't he *cough cough*.