I'm getting quite a bit of submissions of photos that are of sunsets or just late afternoon blue skies.  I'm very sorry to reject them but they don't fall under blue hour photography.  I don't want this group to get off topic.  Also if you don't have any blue hour shots, this is a great time to get out there and try it!! 

Here's how:

Wait for the sun to completely set.  Wait some more till there is almost no visible light, but still a TINY bit of light still learking in the sky. At this point the sky should look really deep blue to your naked eye.  Very dark royal blue but not black yet.  Grab your cam and open your shutter for a few seconds and voila!! you'll get the deepest most vivid blues you can imagine!! 

Good luck. 

Liban