This requires you to beat the computer 10 times at the Sandstalker minigame played during the intervention The Conga Lords: Figaro
or at the video game console in the Twins Room after the intervention. Playing from the console will automatically skip the cutscenes, but you may wish to actually play using the intervention (at least until you unlock the Maduin memento). At the end of each game, a quick win-loss count shows up in the lower right corner. Once the upper number hits 10, you get this achievement.
This game is about equal parts strategy, logic, and luck. With the right starting points and thinking through the info you are given, you should end up well ahead of the computer in wins. If you are trying to actually get the memento, the luck factor is drastically increased.
I found the following video helpful in gaining the memento, but it should also be helpful in understanding the minigame altogether.