To have dinner with Galileo Galileo. It would be an amazing experience. He is not just talented but also genius on his work. He is both artist and scientist.
He can easily see which rich aristocrats to work with and how to impress them. I would ask him about Medici Family. How come he connected the Jupiter and the family. How to get power and how to handle what you have...
How he thinks and what is his process. I kinda want to be fast thinker like him.