I really like the FCBarcelona colours. And I was inspired to make a hat (well, not only because of the colours, I have a Barça fan in the family as well). I've also made the pattern available for others. But for the moment, there is something wrong with the Ravelrys download link. Ravelry users can find the pattern here. Others can make a comment, and I can give them an expiring link to the pattern (that seems to work). The pattern is free of charge. If you wish, you can do as Barça, and support UNICEF. (Pattern only gives measurements in cm, assuming that most Barça fans are metric.)
UPDATE: Pattern can now be found here.