As I said last time, I'm going to talk some more about time travel. Because I love it. What does this have to do with upcoming Camp NaNo? Probably nothing. And that's okay.
Here's my experience with time travel. I've written two time travel stories. I think. I can only thing of two. I have Unknown Soldier (first written as a short story in 2008, then as a screenplay in 2011), and A Matter of Time (my first NaNo from 2010).
Unknown Soldier was pretty straightforward. It was a loop. Essentially, our protagonist heard a story about a mysterious guy who did a heroic thing. This inspires him to try to be heroic. He volunteers for an experimental program to test, you guessed it, a time machine.