I woke this morning with Pachelbel's Canon in D played by a Game Boy synthesizer stuck in my head.
This occurrence is intriguing because while I have heard Pachelbel's Canon many times, and while I have heard music played on a Game Boy synthesizer many times, I have never heard Pachelbel's Canon played on a Game Boy synthesizer before. Yet there it was, playing through my head.
Even more interesting: I realized later on that the canon playing through my head was at least in parts in a minor key, while the actual canon is written in D major.
So completely unbidden by conscious thought, for no reason known to me, while I slept my brain spun together a novel arrangement of a song it knew and an instrument it knew, and then transposed it to a minor key.
By now, however, various other songs have crowded it out. If only I had a USB port for capturing such things...
*I have some basic musical inclination, but nothing special, and I am not nearly as avid of a music listener as many others I know. Yet I virtually always have something playing in my head, which I understand to be relatively rare. I think my dad was the same way. Curious.