During the game, hit the Ctrl+Alt+Shift+C keys simultaneously. A box with a flashing cursor will appear. Type one of the following and press enter to activate:

PAY TRIBUTE TO YOUR KING - gives you all the extra gifts
POWER TO THE MASSES - gives you access to all power plants regardless of the date
WATER IN THE DESERT - gives you access to all water plants regardless of the date
NERDZ ROOL - turns your industries high-tech
STOP FORCING ADVICE - turns off your advisors
I AM WEAK - construction costs are set to $0
CALL COUSIN VINNIE - $250,000 donation offer
ZYXWVU - gives you the SimCastle structure if you turned down Vinnie's offer
SALT OFF - turns the seas into fresh water
SALT ON - turns the seas back to salt water
TERRAIN ONE UP - raises the selected terrain by one
TERRAIN ONE DOWN - lowers the selected terrain by one
TERRAIN TEN UP - raises the selected terrain by 10
TERRAIN TEN DOWN - lowers the selected terrain by 10
LET'S MAKE A DEAL - neighbors will start trying to make deals with you if you are connected to them in some way (power, water, roads)