i) births and deaths
30 July 2015: death of Clifford Earl who played the police station sergeant in the original Christmas Day episode, The Feast of Steven, part of the story we now call The Daleks' Master Plan (First Doctor, 1965), and also Major Branwell in The Invasion (Second Doctor, 1968).
ii) dates specified (or almost) in-universe
30 July 1864: The Fifth Doctor rescues Nyssa from the fighting around Peteresburg, VA in the U.S. Civil War in the 2007 audio Renaissance of the Daleks.
30 July 1977: Most of episode 1, all of episode 2 and the first part of episode 3 of Image of the Fendahl (1977) appear to be set on this date, for reasons which will be explained tomorrow.