Knitlympics: Knit Your Favourite Sports Star looks like such a fun book. It has been published in preparation of the UK summer 2012 Olympics.
"Includes patterns for 20 Olympic icons, from ancient Greece to London 2012. You don’t have to be athletic to knit your own lighting-fast Usain Bolt, mustachioed Mark Spitz or sparrow-like Olga Korbut."
There are also pattens so you can customize your tribute to your favorite athlete.