I've been playing an online webgame recently. (You've probably seen the advertisements for it). The game is one where you build up your empire in several ways in order to dominate your corner of the world.
One of the ideas of the game is that the game runs even when you aren't online. You're farms keep producing food, your ironmines keep creating iron, and so on. You leave it for a day, when you come back you have the resources to build something you've had your eye on. The game teaches you patience. After you start getting some of the higher level buildings and warriors or technologies it can take days to accomplish one thing. (During which you hope you won't be attacked).
I like this aspect of the game, as it will keep users coming back again and again.
One of the downsides of the game is that it plateaus fairly quickly. The game design is good, but doesn't go far enough. It also doesn't have enough possible paths in order to advance your "civilization". The game does copy a lot of ideas from civilization, including most of the quotes.
The game is downloaded into flash each time you log in, so it is kept updated in real time.