Dance is the art of movement of the body, usually rhythmically and to music, using prescribed or improvised steps and gestures. "A dance" is any one prescribed sequence of such movements, or the music to which it is performed, or an event at which it takes place. Dance may also be regarded as a form of nonverbal communication recognisable in other animals; in bee dances and behaviour patterns such as mating dances.A party is a gathering of people who have been invited by a host for the purposes of socialising, conversation, recreation, or as part of a festival or other commemoration of a special occasion. A party will typically feature food and beverages, and often music and dancing or other forms of entertainment.Shab-e Chella(-ye bozorg) ("night of (the great) forty", Persian: شب چلّه) or Shab-e Yaldā ("Yalda night" Persian: شب یلدا) is an Iranian festival celebrated on the "longest and darkest night of the year," that is, in the night of the Northern Hemisphere's winter solstice. Calendarically, this corresponds to the night of December 20/21 (±1) in the Gregorian calendar, and to the night between the last day of the ninth month (Azar) and the first day of the tenth month (Day) of the Iranian civil calendar.
The longest and darkest night of the year is a time when friends and family gather together to eat, drink and read poetry (especially Hafez) until well after midnight. Fruits and nuts are eaten and pomegranates and watermelons are particularly significant. The red colour in these fruits symbolises the crimson hues of dawn and glow of life. The poems of Divan-e-Hafez, which can be found in the bookcases of most Iranians families, are intermingled with peoples' life and are read or recited during various occasions like this festival and at Nowruz.