Kirk (Chris Pine) and Spock (Zachary Quinto) in J.J. Abrams' Star Trek .
My favorite Star Trek episode is called "Cause and Effect." Here's the setup: the crew members of the Enterprise (the Enterprise-D , since we're in Next Generation here) are trapped in a time loop. They repeat the same sequence of events over and over again. At the end of each loop, the Enterprise is destroyed in a catastrophic collision with another ship, and they go back to the beginning. But with a subtle difference: each time they go through the loop, it leaves behind dark trace memories, so the next time around, the crew is haunted by a sense that something terrible...
