Doctor Who: Lockdown!

Doctor Who: LOCKDOWN! (originally titled Who at Home ) was a concept founded by Emily Cook from Doctor Who Magazine who proposed the idea to Doctor Who fans as a simulcast watch-along of the show's 50th Anniversary, The Day of the Doctor, worldwide as a way to pass the time in self-isolation due to worldwide outbreak of COVID-19. The story was shown on 21 March 2020. She added that if the concept gained enough popularity, she would arrange more watch-alongs.

For the first watch-along, Steven Moffat penned a short introductory skit, Strax Saves the Day, which was released on Twitter. The home-produced video starred Dan Starkey as Strax, represented on screen with a stuffed toy of the character, and featured the voice of Neve McIntosh as Vastra.

For the second watch-along Russell T Davies released a previously withheld prequel short story, Doctor Who and the Time War, which was released onto the Doctor Who website and depicted an alternate account to the Eighth Doctor's involvement in the Last Great Time War and the Ninth Doctor's origins, and a sequel audio story, Revenge of the Nestene, which was released onto YouTube and depicted the aftermath of the Nestene Consciousness's defeat at the hand of the Ninth Doctor.

Watchalongs

 * The Day of the Doctor (21 March 2020) (this watch-along reignited #SaveTheDay)
 * Rose (26 March 2020) (15th Anniversary, #TripofaLifetime)
 * Vincent and the Doctor (30 March 2020) (Van Gogh's birthday, #TheUltimateGinger)
 * The Eleventh Hour (3 April 2020) (10th Anniversary, #Geronimo)

Associated stories
Several new short stories and webcasts were released to tie into the watchalongs, or the COVID-19 pandemic in general.