I've just followed a link from Year of Finishing Off to a pattern for spiral socks at Marlies' Creative Universe. I followed it because my feet are cold - finally, a proper winter in Melbourne! - but when I saw the pattern can be adapted for babies and is easy to knit, I thought of Penny.
Sometimes she licks her paws and when I put medication on her feet she attempts to lick that off, which has the pleasant result for her that she gets a Kong to lick. As we're trying to keep her weight down, so there won't be too much strain on her legs, it would be good to have little socks to put on her feet. (The shoes didn't work too well!)