One standard 52-card deck, shuffled.
The goal of Monte Carlo Solitaire is to remove all of the cards from the table in matching pairs.
Deal 25 cards onto the table, forming a 5x5 grid. Set the remaining cards to the side, forming a face-down draw pile.
Matching pairs (e.g. two 4s, two Js, etc.) can be removed from the table when they are next to each other horizontally, vertically, or diagonally. Any cards removed in this way are discarded.
Once a player removes all of the pairs that she wants to (there are times when it makes strategic sense not to remove a pair), the board is consolidated. Consolidation involves filling in the gaps by moving cards to the left, and up a row if necessary.
The empty spaces on the board are then filled in with cards from the draw pile. NOTE: When the draw pile is empty, consolidation still takes place but without this final step.
The game continues until either all cards have been discarded, or no further legal moves are possible.
A player wins by matching and discarding all 52 cards.
Monte Carlo Thirteens is a closely related solitaire card game.