James T. Kirk/Time travel/Other temporal events

A visit to the planet Sarpeidon, doomed by its sun's impending nova, revealed that the Sarpeidans had escaped en masse into their own planet's past via their Atavachron time portal. The harried and ubiquitous Atoz mistook Kirk, Spock, and McCoy for tardy natives, and he thrust them into the planet's past. ()
In 2269, Kirk and Spock used the Guardian of Forever a second time, on a mission of historical observation to the dawn of Orion civilization. Upon their return, no-one but Kirk recognized Spock as the Enterprise first officer. Supposedly killed in his childhood, Spock returned to the Vulcan of his youth, playing the role of a nearly forgotten cousin who had saved his life during the kahs-wan, a Vulcan coming-of-age ordeal. ()