RISK

The quickest and easiest way I found is to set up a game of Capitals with 2 Balanced AIs. Once the game begins, regardless of your starting position, choose a capital that is easy to fortify and has at the very least 3 troops already on it (so you're not using reinforcements on your own capital). When play begins, be very selective about where you go. Using one or two attacks and then fortifying your spaces will serve you well here instead of attacking until you have no units left. Win at least one battle per turn so you can get a card, and SAVE them. If you go slow and keep most of your tiles with at least 2 troops they wont be attacked as much and will win more often, while the AIs wear themselves out on each other and leave you with a nice playing field of 1 troop areas. By your third turn you should be snaking closer and closer to both of their capitals which may no longer be well fortified (the computer likes to use its capital troops on its borders for some reason). At this time, depending on your cards, you may have 4 stars already and control of one of the smaller continents (if you're close to getting one at the beginning, go for it for the troop buff). If you have 4 stars, you can trade them in for 7 additional troops, and dividing those between your two capital attackers should be plenty to take them down. Using this method I can do about 4 games an hour without losing, regardless of starting turn. Not bragging, just saying it's a pretty good bet. Happy hunting!