Palimpsest, by Charles Stross

This is how I love my sci-fi: short and to the point. We still get the Charlie Stross signature nice techie guy who falls for girls in sci-fi settings, but since this is a novella, Palimpsest focuses almost entirely on the catch, the "what if" kernel of the story. And that is another exploration of what time travel would lead to, in this case an out of time organization called the Stasis that exists solely to protect Earth from inevitable extinction by reseeding it with humanity whenever it happens, thus creating a sort of stagnating but stable civilizational time flow that last for trillions of years until the heat death of the universe.

But I liked the little details a lot. As the title suggests, once you can time travel, the timelines can be infinitely rewritten, leading to all kinds of (maybe literally all) possibilities. In order to join Stasis you first need to kill your grandfather and in order to graduate you need to kill yourself in another timeline! Mad and fun ideas are in abundance in the book and I particularly enjoyed that it presented them one after another and then the story ended. No need to take it further to some sort of personal conclusion for the main character. It is pure fantasy and then it ends. Love that!