The term US Open is applied to open (as in anybody, even foreigners can compete) US-American championships in a particular sport. The most prominent ones are:
... biscuit[?] producer (+ 1985)
April 3 - Sally Rand[?], dancer (+ 1979)
April 7 - Ralph Bunche[?], diplomat, winner of the Nobel Peace Prize
April 16 - Fifi D'Orsay, ...