These days, you can fit the contents of a small semi-detached house inside most racquet bags. But while most of us fill the void with a couple of racquets, a can of balls and a moldy banana, players like Agnieszka Radwanska, Caroline Wozniacki and Petra Kvitova use them for dragging the tools of their trade around the world. Tools like Aussie Rules footballs, notebooks and loads of really random stuff: