This book has it all -- nonstop action; a great plot; brutal, bloody fights; a cooler than cool main character; and lots of twists and turns. Kind of like The Hunger Games (spectator sports! battles! revolution!) but about a million times better -- and it's in outer space!
Book 1 of the Red Rising Saga
This book was such a fun adventure/survival thrill ride (with a smidgen of romance). The format comprised of interview transcripts, memos, instant-messaging transcripts, diary entries, and more made for a unique read. (Don't let the size fool you -- it's a quick read with a lot of white space around the pictures, text messages, and such).
Book 1 of the Illuminae Files