The Sims (PC - 2000 - 24 games total)
The world's premier simulation game. Instead of building cities or guiding civilizations, you're nurturing a gibberish-speaking family and arranging their furniture. Their entire existence, quite literally, is in your hands. Your whims decide whether they lead successful lives with meaningful relationships or piss themselves and starve to death.
Why it soared
This must be what it feels like to be a god. First you whip up a being in your own image, then make it toil away for scraps of food while rewarding it with paltry things like toasters and tables. Give it a source of income and something to make out with and poof, it's totally placated. Friendship, parenthood, relationships, everything is your call - even bizarre torture like encasing the Sim inside a brick wall. This overwhelming sense of control is hard to pass up, and the open-ended, living-dollhouse gameplay makes it impossible to reach the "end" at all. Life has no ultimate goal, so neither does this game. It's totally addicting and captured the minds of guys, girls, gamers and non-gamers, pretty much anyone who knew how to move a mouse. It's a cultural touchstone that tens of millions around the world know inside and out.
What it did for the franchise
As the first in the series, it laid the foundation for its numerous expansions. The isometric viewpoint, never-ending gameplay, even the iconic green cursor got its start right here, right from the beginning. Peripheral interests like Sim fashion and architecture grew so large that later games made it a point to focus on these aspects intensely. The fictional Simlish language began in the first game too, which will hopefully not be part of thewoefully unnecessary movie.
Who it inspired
Well, it managed to convince Electronic Arts to make The Sims its own publishing label. Outside the walls of EA, Second Life owes no small part of its success to the ideas started in The Sims, and even a brief glance at PS3's upcoming Home reveals clear parallels. Then there's the floptastic Singles: Flirt Up Your Life, which no one remembers because it was stupid.