One of the oldest events of its kind in North America, the 40th annual Boston Dragon Boat Festival once again graces the waters of the Charles River June 8 & 9. A mixture of Asian culture and competition, the weekend consists of races where more than 70 teams of 22-person crews of paddlers in traditional 39-foot Hong Kong-style dragon boats vie for bragging rights along a 500-meter stretch of the river on the Cambridge side near the Weeks Footbridge. Highlights also include performances, demonstrations, and arts and crafts, as well as a variety of Asian food. This relatively young celebration has a lot of catching up to do, however; the extravaganza was inspired by a legend surrounding the ancient Chinese poet Qu Yuan, and is a 2,000-year-old tradition in its home country.