That's the experience OnLive hopes to deliver, and today marks the opening of the beta program for those who signed up after the company initially went public to the press back at the Game Developer's Conference in March of this year.
Much like what Netflix or Hulu are now doing with online video, OnLive hopes to do with gaming. You'll be able to access the service on PCs and Macs with compatible hardware requirements via a browser plug-in and hop right into multiplayer matches against other players on various platforms (you'll need a broadband internet connection to use the service). Being able to provide true cross-platform multiplayer gaming itself would be rather novel, and the underlying goal of disintermediating the game console is indeed a revolutionary one.
They also plan to offer their own, as they call it, "micro-console" that is essentially a small device big enough to include a couple of USB ports, ethernet, HDMI, and optical audio out. The unit would accept up to 4 wireless controllers and bluetooth headsets, offering an alternative method of accessing the service if you don't have a spare computer to play on and/or hook up to your television set for a living room gaming experience.
Still, it will depend greatly on the underlying technology and if it will be able to handle the significant technical challenges of synchronizing fast-response gaming experiences to multiple players simultaneously on different platforms. In many of the games players will want to enjoy, even a split second of lag time is unacceptable.
If OnLive is able to scale and meet the demand, however, it could pose a significant challenge to a game console industry that's weathered the storm of multiple hardware cycles, but might face an uphill battle against a truly great on demand service. They haven't released an official decision on their business model yet, but OnLive has indicated it will most likely be either subscription-based or possibly subsidized through the purchase of the OnLive micro-console.