This was put together from a couple of patterns, and then played with until I made it work. I had enough yarn left over to make this even after making a pair of women's size 10 socks! I love the big Opal 6ply skeins (this is the Flamingo colourway).
Shelley also has a cute design for some baby socks and a baby hat using left over sock yarn, check it out here (link is to a pdf file) or over on the side in the free patterns link.
Using up sock yarn left overs is just as fun as making the socks, I find. What do you like to do with yours?