I woke up this morning at around 5 AM to a loud crash.  It sounded like it was inside, but after much searching, I couldn't find the source for the noise.  After completing some reconnaissance, I sat on the edge of the bed and started to recollect the event, only to finally wonder whether the crashing noise was part a dream.  I normally don't remember my dreams, so it's entirely possible.  But now I'm still wondering what it was.