Marathon G40:
Come back each day of an entire month and complete at least one Daily Challenge.
Every day, you have five (5) challenges to complete, one for each type of solitaire card game (Klondike, Spider, FreeCell, TriPeaks. The difficulty ranges from easy to expert among the different type of game. But there is at least complete one (1) easy challenge in the lot; Log in every day complete any one challenge in a month and you can get this achievement in the end of the month.