Leaping Labrador Puppies

I don't remember if I said this somewhere in a post, wrote it in an email to someone or just thought about it so much I now think it was real, but I already had plans for what my next book would be.  I was going to restart a speculative piece I worked on last year.  I even have a brand new way to approach it, which is good because the original storyline was feeling 'done to death'. 

I was pretty excited and then last night happened.

Laying in bed (why do ideas always hit me when I'm trying to sleep?), my brain started to take DLN to its next logical step.  Oh, the book itself is self-contained, but I also laid the groundwork so this could work into a series.  And that's where my brain went last night.  I started writing the opening scene, plotting where I wanted the book to go, and figuring out the basic plans for a sequel.

Which, of course, I want to start writing.  NOW.  And I haven't even started submitting the first book in the DLN series. It would just be foolhardy to start the sequel to a book I haven't gotten any interest in yet. 

I already had a book I was ready to write, dammit.  What's up with the damn writerly leap frog?  Why can't books just wait their turn?

To top it off, I usually forget the writing I think up while I'm trying to fall asleep.  This one?  Nope.  It sprang into my head like Athena popping out of her daddy's skull - fully formed and ready for battle.  (expletives deleted.)

So, I wrote it down in my 'to be written' folder.  Just my luck, while I was in there, I read some of the other story ideas I have simmering.  Now they're leaping around in my head begging for attention like a litter of lab puppies. (Pic found online, btw.  I don't have any dogs right now.)

Most likely, I'll set the speculative aside and see where Jo's next story takes me.  If it ends up being a false start, I'll go back to the other book.  If both of them piffle out on me, there's always one of the others - ready and waiting to jump all over me when my back is turned.

Has this ever happened to you?  What do you do about finding your next story when your WIP is almost finished?  Do you have a boxful of leaping labrador puppies begging for attention?