If you were to roll back time, to which era would you roll it back to?

Good question. The short answer is that I wouldn't - I'm reasonably satisfied that one era is as good as another, thus a rollback would only deprive me of my own chronological authenticity.

If, for whatever reason, I did backtrack, then assuming it were possible to do so safely AND return to the present intact, I would love to see the birth of the universe - if such a singular, defining moment ever occurred.

If not, then I'd want to do one of the following: a) pan forward to the moment at which a quantifiable explanation for material existence is discovered*; or, b) fast-forward to the end of time*; or, c) rewind as far as possible.

* That is, if forward time-travel were possible, and/or that time is finite.

Go on, ask another - I dare you.