If you enjoy playing Risk where you aim to takeover the world using your armies then you will probably enjoy playing Imperial Takeover. It is just like playing the real board game but since boards are old fashioned you get to play online against real people for free.
You can either play a game online the now or if you prefer you can spread the game over several days by playing people in different timezones - this lets you spend a bit longer planning your moves at being a megalomaniac.
