I've never finished a novel before, so I've never needed to write a query letter. Despite this, I wrote a query letter a couple days ago. This query is completely fake: written by a fake author to a fake editor about a fake book. I really like the idea I came up with though. I doubt that I'll ever actually write it (because I'm not sure that I'm the best person for the job), but it would be really fun to read.
The idea for The Pride She Carries came from female Kurdish resistance groups. I had the idea in a different sort of setting for the same genre (far-future military SF) before deciding to use the idea for this fake book that my partner and I are using for our proposal for class. I won't post the full pitch, but I'll try to boil it down below.
Chanua, a female war hero, battles a terrorist sect of radicals from an archaic native religion with a group of fellow female warriors. Will the terrorists, who go by the name the Lions' Bane, succeed in taking all of Kenya by storm, or will Chanua and her Huntresses pick them clean to the bone?