8 December 1939: birth of Jennie Linden, who played Barbara in Doctor Who and the Daleks (1965)
ii) broadcast anniversaries
8 December 1979: broadcast of third episode of Nightmare of Eden. The Doctor realises that vraxoin comes from roast Mandrel.
8 December 2009: broadcast of second episode of Enemy of the Bane, concluding the second series of Sarah Jane Adventures. Sarah, Luke and the Brigadier force Mrs Wormwood and the Sontaran into a portal concealed in a stone circle. Last ever appearance (sob!) of the Brigadier.
iii) date specified in-universe
8 December 1926: Setting of The Unicorn and the Wasp (2008), where the Tenth Doctor and Donna meet Agatha Christie.