The tomb of Imamzadeh Eshaq-ebne Musabne Jafar is in Sarcheshmeh of Gorgan. He was Imam Reza's brother. One of the Rituals relevant to this Imamzadeh is that on new year thousands of people collect in this vicinity and at the end of this ceremony, everyone receives cards, sweets and coins.
Reference :www.itto.org