A fair (archaic: faire or fayre) is a gathering of people to display or trade produce or other goods, to parade or display animals and often to enjoy associated traveling carnival or travelling funfair entertainment. It is normally of the essence of a fair that it is temporary; some last only an afternoon while others may last as long as ten weeks. Activities at fairs vary widely. Some trade fairs are important regular business events either where products are traded between businesspeople, as at the Frankfurt Book Fair, where publishers sell book rights in other markets to other publishers, or where products are showcased to consumers, as for example in agricultural districts where they present opportunities to display and demonstrate the latest machinery on the market to farmers.