Fly (or "jump" from any point on earth to another in an instant).
Walk through anything. Go invisible at will. Stop a jumbo jet in midair. Read people's thoughts. Withstand extreme temperatures.
Etc.
Any super power of YOUR choice.
But you can have only one.
What would that be? And, What would you do with it?
Me? I'd like to be able to use how to use ANY instrument - musical or any machine - like the devil himself.
What would I do with it?
I'd call up some people to jam.
But also for myself, when alone, it would provide me with great solace and pleasure to just whip out tune.