Wikipedia
Hoopfest
Hoopfest is an annual 3on3 basketball tournament. Such an event can be held for several means. Examples are for a charity, physical activity, disease curement, and most commonly human spectation. The idea sees two even teams oppose each other in various games of basketball where the advancing teams continue to fight until there is a declared winner. This event is usually held on street areas (very common) with basketball courts and/or in a parking lots.
The largest and most relevant 3-on-3 basketball tournament in the world happens on the last weekend of June annually in Spokane, Washington. (See: Spokane Hoopfest).