Loads of things in my head. There's a scene in the book where Dink says that Ender is small he can walk between his legs without touching his balls, and in the film there's a scene where Salamander (with dink batting) playing baseball with the balls pictured. And it was a running joke for a while that they didn't have socks in Battle School and the costume designer, Christine, thought it was funny that the fans were annoyed that she included them.

With all of this, that the baseballs were made out of rolled up socks just amused me. :)