The Inner Light

Picard is struck by an energy beam from an alien probe, which renders him unconscious and places him in the life of a citizen on the planet Kataan, with his memory of the Enterprise intact.  Although he searches for a way to return, he finally decides to live his life with his Kataan wife, have children & grandchildren, learning to play a flute and completely immersing in the Kataan culture. He finds the planet is dying due to an imbalance of its sun.  With no way to evacuate the planet's people, the government builds a probe which will tell others how they lived.  The same probe that Picard met.  Picard wakes to find himself back on the Enterprise having lived an entire lifetime in just minutes.  The probe, having disgorged its memories, gives one last gift:  the flute (which shows up in later episodes.)