The day that falls two days before Lent is called Bolludagur or Bun Day. Traditional cream puffs, the “buns,” are served in homes and restaurants and every bakery in town sells them around this time. Bun Day is followed by Sprengidagur or Bursting Day, when people eat a meal of salted meat and peas until the point of near “bursting.”

Source: http://traveltips.usatoday.com/holiday-traditions-iceland-16065.html