22 September

On 22 September 1960, Tegan Jovanka, companion to the the Doctor in his fourth and fifth incarnations, was born in Brisbane, Australia.

On her 46th birthday in 2006, Tegan was reunited with the Fifth Doctor when he found energy spikes on this date in Brisbane. Katherine Chambers, a friend of Tegan's who'd previously met the Sixth Doctor on 28 December 1984, had used the Cyber-technology left behind by that occasion to help "cure" her brother by converting him. She tried to do the same to Tegan to help with her brain tumour, and then move on to converting the whole world. The Doctor managed to stop her, and finally got a proper goodbye from Tegan.

22 September was also the birthday of a British pop star named Billie. (AUDIO: The Gathering)
 * Although the radio turns off mid-sentence, this is a likely reference to Billie Piper, an actor and singer who was indeed born on this day.