Just downloaded Lucky Thirteen by Marko Kloos from the Kindle Store. It's a short story set in the same universe (why don't we use Heinlein's term "ficton"?) as his novel Terms of Enlistment.
And none of the Usual Suspects mentioned this was coming! Even at least one who posted a review on Amazon, but never mentioned it (that I saw) on her blogs or Facespace. Harumph! (Marko posted about it, I really need to hit the RSS feeds a little more assiduously...)
Anyway, short story. Terms of Enlistment universe.