(Slightly off track, re FTL): a. Who says Einstein is 100% right? b. There are "work-arounds" that do NOT violate Einstein's theory: one is to actually ALTER the speed of light. We have tons of ways to make it slower (that's why images are distorted looking through water, etc.)

As far as "big" questions, mine are definitely geeky:

1. What is dark energy, and gravity for that matter, really?
2. Will the expanding definition of "life as we know it" allow for a liquid medium other than water?

And a somewhat silly one:

Why do cats make that face where they scrunch up their upper lip?