Ask him about 3D printing, robotics, the Hyperloop, or anything.
http://www.reddit.com/user/JordanBrandtFuturist/
<update> The live asking of questions is over but you can see the discussion: http://www.reddit.com/r/IAmA/comments/1q1yep/dr_jordan_brandt_here_tech_futurist_hyperloopster/