Chess Marathon
In order to obtain this secret achievement you need to play a very long standard live game and make at least 100 moves. Good luck not falling asleep! 
Note: don't forget about the 50 move rule: a player can claim a draw (on chess.com the game might be drawn automatically) if no capture has been made and no pawn has been moved in the last 50 consecutive moves (50 moves by each side).
