Star Trek: 10 MORE Greatest Time Travel Episodes

2. Those Old Scientists

Star Trek has had a muddled history with crossovers, time travel or no. Trials and Tribble-ations set the bar extremely high (see our previous list), whereas 'that-one-on-the-holodeck' plundered the depths of a series-ending low. When a new crossover was announced, we had reason to get our hopes cautiously up. Those Old Scientists did not let us down. Because we all love grapplers.

The cause of time travel is straightforward; the effect is not. We were all wondering how the switch from animation to live action would be made. Those Old Scientists achieves the transition with impressive ease. Even the title sequence crosses over without the need for questions. Boimler and Mariner go IRL as if they aways had been. Puzzlement paints a thousand words.

'A California Yankee in Captain Pike's Quarters' doesn't quite have the same ring to it, but it is just as fun. Boimler's boimlering around the temporal prime directive, a certain Vulcan, and one Number One, is simply a joy to watch. In all that, Mariner also proves that you should always meet your heroes, whenever they happen to be.