Technological spinoffs are an obvious one. I would be interested to know how zero gravity can be turned into cash. Ball bearings for gyroscopes for instance. Metallurgy is another. It would be very interesting to see what new alloys could be produced. Tourism has limited potential at this time due to the high cost of getting people into orbit. Space based energy systems intrigue me. Solar power 24/7. Mining He2 from the moon. Advertising revenue? Would it be legal to put a pizza hut symbol across the face of the moon?