None that grabbed me
ii) broadcast anniversaries
22nd August 1964: broadcast of 'A Change of Identity', third eisode 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...
22nd 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. In response to queries from Alex, it seems that the story was broadcast twice fortnightly rather than weekly; I don't know if that was also true for Pirate Radio Four in which it was embedded.
iii) dates specified in canon
22nd 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)
22nd August 1941: climax of the earlier timeline of Gary Russell's 2008 Torchwood novel, The Twilight Streets.