22 August 1925: birth of Ivor Salter, who had three roles in Old Who - the Morok Commander in the story we now call The Space Museum (First Doctor, 1965), Odysseus in the story we now call The Myth Makers (also First Doctor, 1965) and Sergeant Markham in Black Orchid (Fifth Doctor, 1982). But for my selfish purposes, he was also the semi-regular policeman in Here Come the Double Deckers!
22 August 1959: birth of Mark Williams, who played Rory's father Brian Williams in two 2012 Eleventh Doctor stories.
ii) broadcast anniversaries
22 August 1964: broadcast of 'A Change of Identity', third episode of the story we now call The Reign of Terror. Susan and Barbara are rescued; Ian escapes; the Doctor disguises himself as a Regional Officer (magnificent uniform), but the jailer has rumbled him...
22 August 1985: broadcast of episodes 5 and 6 of Slipback on radio. Eric Saward still thinks he is Douglas Adams and the Doctor manages not to prevent the Big Bang.
iii) dates specified in canon
22 August 1572: The Doctor reappears, and he and Steven make it back to the Tardis, leaving poor Anne Chaplet to face the awful events of the following day. (as shown in The Massacre, 1966)
22 August 1941: climax of the earlier timeline of Gary Russell's 2008 Torchwood novel, The Twilight Streets.