@batman12 dude! Ask them if they've ever seen you and Bruce Wayne in the same room :')
There's a few articles on deep diving that will give you a lot of suggestions on the main site. Remember it's deep diving, so you dive into their answers. A lot of "why?" questions from their answers is a cheat to exploit it.
When you were little, what did you want to be when you grew up? - feel free to tease them here or joke that you wanted to be superman... then ask why? This will give you more depth to play with.
They wanted to be a teacher? Why? Run with this - if they were inspired by a good teacher, what made them good? Why did they like their classes?
Why are they interested in this or that, how did they get in to it. Every deep dive is different due to exploring their experience and thoughts.
If you still want suggestions
What did you want to be when you grew up?
What's your dream job?
If you could go anywhere in the world right now, money no object, where would you go?
What would you do if you won millions?
What got you into that hobby?
What's the most interesting place you've been?
Best childhood memory?
Favourite film/book/play?
Ask about jewellery/tattoo etc
Do you come here often? (Haha)