It has been a tradition all over Iceland to celebrate "Þorrablót" and before it was a matter of religion but now it’s all about enjoying each others company and eat the traditional food.
Svið. The centrepiece of any Þorrablót (a Þorri celebration offering the food) is svið; seared lamb heads. While every part of the head is edible, including the eyes and ears, the tastiest part by far is the jaw muscle. Not that the eyeballs are without their charm – done right, their taste resembles a slightly chewier version of boiled eggs. Svið is often available all year.
Sviðasulta. The meat from svið, compressed in gelatine. For those too squeamish to eat food that stares at them.
Hrútspungar. Ram’s testicles, usually soaked in mýsa (whey – which has a sharp, citrusy flavour). As the mýsa is usually the only thing you can taste, you’re left instead with the soft, crumbly texture of the nads themselves. Not entirely unpleasant, but nothing to push people out of the way to get, either.
Slátur. There are two types of slátur: lifrarpylsur (liver sausage) and blóðmör (blood sausage). The former is ground liver mixed with rye meal boiled in a sheep intestine casing; the latter is the same, only substituting the liver with blood. Lifrarpylsur naturally tastes like liver, which you either love or hate, whereas blóðmör has a wheaty, slightly beefy taste to it. Some people sprinkle sugar on these items. These people are regarded with scorn and disdain.
Lundabaggar. Various and sundry internal organs from sheep, rolled up into a net, boiled, and soaked in mýsa. This is a pretty fatty dish, one that should be savoured. Fans of the Scottish dish haggis will find this especially appealing.
Some foods served at a Þorrablót can be found all year. Apart from svið, there is also hangikjöt (smoked lamb), harðfiskur (dried haddock), lifrarpylsur (liver sausage),flatbrauð (flat bread), rugbrauð (rye bread) and hákarl (putrefied shark). All hákarl has an ammoniac flavour to it, thanks to the ureic acid in shark flesh, but the white flesh – as opposed to the brown, marbled portions – are a lot easier to take, as while the flavour is stronger, the texture is softer than the marbled pieces.
http://www.youtube.com/watch?v=xwJYWEEL6wc&feature=related