Ask HN: What interesting problems are out there to be tackled?

I always find myself inspired to tackle challenging, intriguing, interesting problems but I struggle finding those which seem humanly possible or remotely feasible. Of course I understand that it's paradoxical to want to solve yet unsolved problems that appear to be solvable - if they were so apparently solvable then they would have already been solved.

Ignoring that paradox, and taking my personal ability out of the equation, what problems do currently exist that a capable, inspired mind could set themselves to tackling?