Con·viv`i·al'i·ty noun ; plural Convivialities The good humor or mirth indulged in upon festive occasions; a convivial spirit or humor; festivity. Found on http://www.encyclo.co.uk/webster/C/154
conviviality 1. A jovial, sociable, friendly, and lively disposition or nature. 2. The good humor and festivity indulged in during occasions of celebration. Conviviality is derived from Latin convivium, 'banquet'; from com- + vivere, 'to live'; so think, 'banquet of life'. Found on http://www.wordinfo.info/words/index/info/view_unit/2318/