Hong Kong Dragon Boat Festival. Charles River between JFK Street & the Western Avenue Bridge. 12:00 p.m. to 5:00 p.m.  Spectators will be able to watch brightly colored dragon boats, piloted by rowers from Greater Boston, New York, and as far away as Canada, as they race down the Charles River. The festival will include more than 30 teams competing in four categories and a special heat devoted to breast cancer survivors. It will also feature Chinese arts and crafts, a Dragon & Lion dance, martial arts, authentic Hula and Tahitian dance, Korean Poongmul drumming, Chinese dance & music, traditional Japanese festival drumming and Asian food. Free. Will he held rain or shine. (617) 504-5425.