I love when random bits of dialogue and scenes pop into my mind. They are usually unrelated to my current draft or any of the books I have outlined thus far. That's a little scary as it potential adds a book to the series. But really, I love that, too. Perhaps I'll eventually grow tired of living space adventures through my characters, but not in the near future.
For now, I'm filing these random strokes of genesis away. Most of them won't make it to book length. But they'll make dandy short story spin-offs to the series.