Sony is an official sponsor of the 2014 FIFA World Cup, and as such it's prepared its very own theme for its Xperia phones in time for the start of the tournament. While the theme hasn't been officially released just yet, it has managed to leak out online, where it's available to download for Xperia phones running Android 4.3 and above.
Like all Sony's device-wide themes, the World Cup theme touches every area of the phone's software, offering its own custom soft keys. Just about every color, icon and background has been changed with a new football (or soccer, if you insist) themed additions. There's still a full month to go until the World Cup gets underway, but if you can't wait, you can download the leaked version from the source link. Presumably it'll hit Google Play closer to the start of the tournament.
Source: Xperia Blog