This is a great list of homemade dog toy projects, and they range from easy to more difficult. I, personally, wouldn't make anything out of socks, so that your own socks never get confused for a toy, but there are many other great ideas here.
Cat Amazing - Best Cat Toy Ever! Interactive Puzzle Box Game for Cats: Interactive cat toy - game & puzzle - for cats! Encourages natural instinct to explore, sniff, search and retrieve hidden rewards Three levels to stimulate & challenge cats as their skills improve Works with their favorite treats & small toys Makes a great gift!