In the Holiday 2007 issue of KnitSimple, there is a pattern for a "Snug Harbor" by Rae French. Ms. French is the Founder and CEO of Hugs for Homeless Animals and she designed this Snug Harbor to be knit for animals that live in shelters as part of the Snuggles Project. If you would like to help out with this project by knitting some Snug Harbors, please go visit the above link.
We have an outside cat that we allow inside sometimes on the weekend and he's been lying on a flat piece of knitted fabric. When I saw the pattern for the Snug Harbor, I knew I just had to make it for him. It is knit in the round and then decreased similar to a hat and that's what makes it spiral in the middle. You then take some quilt batting to make a nice rounded padding around the sides which helps snuggle the cat (or small dog if you prefer) and it even gives them a little pillow to lay their head.
I used Lion Brand Homespun in the Tudor colorway, it took a little over 1 skein. The pattern suggests that you stripe it with a darker color, but I decided just to make it one color and the yarn striped on its own. This was easily a weekend project even with the seaming and the padding.
As you can see, Bosephus already loves it and he snuggles in it.