Hi Tanya!

It'd probably be Jesus Christ. I would first check if he indeed said some of the things that he's purported to have taught. Then, I'd ask him his opinion on all the crazies out there that do some unspeakable things in his name.

After that, I'd ask him to turn a few dozen bottles of water into some really, really good wine, so I can keep them on the side.

Then, I'd ask him to tell me what the next Google search algorithm will be like... you know, for SEO. He ought to know that, right? :)