Google Now for Chrome OS and Windows is on the way according to Chromium builds

Google will soon bring Google Now, it's intelligent search product for Android phones, to the desktop. The latest Chromium build shows signs that Google Now cards will break free from being a smartphone product and appear on the larger screens of desktop computers. Chrome enthusiast François Beaufort discovered that Chromium has references to Google Now that are currently inactive and private, so it cannot be used at the moment, but they signal that the enhanced search features will be included in the browser.

Once active, Google Now on the desktop could conceivably deliver mostly the same information presented to users on a smartphone. Now shows updates to news stories read, calendar reminders, airline and hotel booking, sports scores for favored teams, directions to appointments, interesting places to visit, and much more. It has so far been made available only to Android 4.1 Jelly Bean users, but support for Microsoft Windows and Chrome OS would greatly expand the service's reach.