Here is what I did to land on 15 Mega Maniac squares in less than 60 minutes:
-Go to Pictionary Mania and set it to "Shortest" & select "4 Players".
-When the game loads up, if the 2 flashing white squares are not within 6 moves of your starting characters then reload a new game.
-When it comes to rolling the dice to move your character count out how many moves you need and if the dice doesn't land on the number you need hit start and quit.
-If you did it fast enough (if the announcer begins speaking prior to you pressing start then you are taking too long) you will be back where you where before you rolled the dice.
-If you messed up just lose on that turn and repeat with one of the other players.
-Once you land on the 2 flashing squares and answer the questions correctly you can safely quit to the main menu and repeat until it unlocks.
The achievement should unlock as soon as you get 15 Mega Maniac answers correct.