Step One: Buy and own as many buildings as you can.
Step Two: After owning a comfortable amount of buildings in the game, Save your game and sign out of Xbox Live.
Step Three: Back all the way out to the Xbox Dashboard, go to your settings, and under your System Settings. Set your Time (Date) as far to the future as you can go, save your settings, but DO NOT sign back to Xbox Live!
Step Four: Reload the Fable II game, load your saved game. In about Ten seconds after loading your saved game, you should earn the 'Big One'. At this time you may sign back on to Xbox Live and not worry about the Time since it automatically updates to the correct status. Save your game and/or enjoy the 'Big Paycheck'!
Note: This is a pretty old trick that most player used. I thought it would be possible to supply the information here as well.