At least one tabloid newspaper here in the UK is reporting that Materazzi called Zidane the son of a terrorist whore (he has Albanian roots - presumably on his mothers side) to cause the headbutt.
If you’ve no idea what I’m talking about, Zinedine Zidane, apparently one of the best footballers in the world ended his career on a low note by getting sent off for headbutting an opponent in the final of the 2006 FIFA World Cup.
Here are some images of the headbutt in all it’s glory. I don’t know where these images come from. If you can reasonably prove they’re yours I’ll give you credit.