My favorite episode of Star Trek NG was when Picard is mentally abducted and thinks he's on another planet for years and years and he has a gift of a whistle that he gradually learns to play rather well. Only to find out the planet died long ago and he was just a way for them to be remembered. He ended up with the whistle to remind him of the "life" he had on the planet.
I didn't know it was a whistle, I though it was some sort of flute.
Saw that one again this weekend. One of my favorites too. Loved the fact that the flute showed up in a later episode.