There's a new breed of online games out there since the last time I was looking.
Normally, the term "real time" means something fast paced that doesn't wait for you to think about what you want to do. These days, on the web, "real time" means just that...actions take minutes or hours to complete.
Take Knight Fight, for example. You take on the role of a knight, and can choose to be good or evil, or somewhere in between. You go on missions, you can attack or be attacked by other knights, get better at your skills and buy better equipment. Missions take a certain amount of real time. You get one hour a day of missions that gain you experience (experience is what you'll use to improve skills), and the rest of the time can be spent on missions that gain you gold (which can be used to buy new equipment, and for other things). You want to spend your gold when you get it, since if you're defeated by another knight they'll steal part of your gold.
Tribal Wars is another example of the new breed of online real time games. It's a basic resource management game, with the option of attacking other villages or teaming up with other villages for protection. All actions take a certain amount of real time. Tribal Wars is nice in that when an action is complete they send you an email letting you know. The email contains a link that takes you right to your village so you can plan your next action.
Various other games limit you on the number of actions you can take each day (e.g. Kingdom of Loathing), but the new games are more tied to each action taking a certain amount of real time. And from the standpoint of a website trying to get repeat traffic, that makes a lot of sense. Visitors return on a regular basis to take their next actions in the game.
These games are all free to play. Presumably they're supported by advertising, although most of the advertisements seem to be for other free games of the same type.
In any case, they're a nice diversion every now and then during the day.