As part of Steam's Holiday event, if you play Red Orchestra 2 today and get the achievement "Fighting The War on Christmas - Participate in a successful territory capture on Commissars House" in RO2 you can win a prize on Steam!!! These prizes include free games, free DLC, coupons for % off of games, and more. So get in game and get that achievement now!!! For more info check out the Steam Holiday Event Page.
Note: if you already have the achievement you can still get a prize. Keep in mind that prize may be a lump of coal. But also keep in mind, as Steam says on the page lumps of coal can be crafted into prizes, or give you a chance to win EVERY GAME ON STEAM at the end of the event.