25 December

25 December was the traditional date of Christmas Day. (TV: Voyage of the Damned)

Amongst the notable things that occurred on this day were:
 * 1851 - The Cybermen created by Cybus Industries attempted to conquer Earth, but were stopped by the Tenth Doctor. Their accomplice, Mercy Hartigan, was converted into a Cyberking and used her mind to assume dominant authority over the other Cybermen, but the Doctor broke the connection between her and the Cybermen. She quickly went into a panic, causing an electrical overload that disintegrated herself and the Cybermen. Jackson Lake learned he had gained the Doctor's knowledge through exposure to a backfiring infostamp and rescued his son from the Cybermen. Lake also invited the Doctor to Christmas dinner after some coaxing. (TV: The Next Doctor)
 * 1914 - The Ninth Doctor and Rose Tyler visited a World War I battlefield and participated in a football match between the British and German soldiers. (COMIC: The Forgotten) Elsewhere on the Western Front, the Fifth Doctor witnessed another such football match while temporarily separated from Peri Brown. (PROSE: Never Seen Cairo) The First Doctor, Steven Taylor and Sara Kingdom likewise visited the Western Front at this time. (PROSE: The Little Drummer Boy)
 * 1938 - The eight-year-old Alistair Gordon Lethbridge-Stewart was given a box of toy soldiers by his namesake paternal grandfather, who promptly asked, "What do you want to be when you grow up?" Alistair was not pleased with his present. (COMIC: The Warkeeper's Crown)
 * 1965 - The TARDIS materialised outside a police station. The First Doctor, Steven Taylor and Sara Kingdom were arrested. (TV: The Daleks' Master Plan)
 * 1976 - Leslie, a future passenger of the SS Elysium on the trip where it would meet its demise to Cybermen, was born. (PROSE: Iceberg)
 * 1981 - Sarah Jane Smith, Brendan Richards and K9 had Christmas dinner in the home of Howard and Juno Baker in Moreton Harwood. (TV: A Girl's Best Friend)
 * 2004 - The First Doctor, Ian Chesterton, Barbara Wright and Vicki Pallister became trapped in a time loop in the home of George Smythe, his wife Patricia and his children of Josie and Mark. (PROSE: Every Day)
 * 2006 - The newly regenerated Tenth Doctor stopped an invasion of Earth by the Sycorax. (TV: The Christmas Invasion)
 * 2008 - Astrid Peth sacrificed her life to kill Max Capricorn onboard the spacegoing replica of the RMS Titanic, also called the Titanic. The control of the Heavenly Host passed to the Tenth Doctor, and they helped him narrowly avoid a planned collision with Buckingham Palace. (TV: Voyage of the Damned)
 * 2013 - After an absence of two years, the Eleventh Doctor joined Amy Pond and Rory Williams for Christmas dinner in Cheldon Bonniface. (TV: The Doctor, the Widow and the Wardrobe)
 * 2017 - The Chelbil invaded Earth. They were scared away from the planet by the Eighth Doctor and Goilin B. After the departure of the Chelbil, the Doctor planned to invite Jason Kane, Bernice Summerfield, Ace and Grace Holloway to Christmas dinner. (PROSE: Not in My Back Yard)
 * 2058 - The crew of Bowie Base One celebrated their first Christmas on Mars. They ate dehydrated protein for Christmas dinner. (TV: The Waters of Mars)

Alternate timeline
In an alternate timeline, on 25 December 2008, the collision of RMS Titanic into London was not stopped and the city was destroyed in a nuclear blast, caused by the ship's nuclear storm drive exploding. This timeline was later negated when Donna Noble was hit by a truck, preventing her younger self from turning right, which had started the timeline in the first place. (TV: Turn Left)

Behind the scenes
This was one of only three instances where a new series Doctor Who television story, namely part one of TV: The End of Time, took place on the same day as its broadcast: 25 December 2009. The other two occurrences were 22 April 2011 and 26 June 2010.