None that caught my eye.
ii) broadcast anniversaries
26 October 1987: broadcast of fourth episode of Paradise Towers, In a final confrontation, both Pex and Kroagnon are killed, and the inhabitants of the Towers look forward to a new future.
26 October 1988: broadcast of fourth episode of Remembrance of the Daleks. Grand battle between the Dalek factions; the Doctor destroys Skaro and also forces the Black Dalek to explode.
26 October 2010: broadcast of second episode of Death of the Doctor.
iii) historical event in canon
26 October 1881: The gunfight at the O.K. Corral, as witnessed by the First Doctor, Steven and Dodo in The Gunfighters (1966).