I always thought the question of which came first, the chicken or the egg was an interesting one.  There's certainly no intuitively easy answer to it.  Evolutionary scientists could probably provide an answer of some sort by tracing back the fossil record or whatever, but I'm just going to go out on a limb here and say what if time travel was involved?  What if somebody with a time machine got themselves some fertilized chicken eggs from now and traveled back to a pre-chicken era and let the eggs loose so to speak? And the whole chicken and egg thing is really, in fact, a giant time loop?  

That'd be pretty crazy.