There are probably different levels to on-boarding:
-For fresh out of college...adjusting to work generally.
-For more seasoned folks...
probably goes general atmosphere (maybe government, TSP, etc)
-rough landscape (your department, mission, values, etc)
-micro-level (wheres coffee, how do we fill out time, who is cool in the office, best local restaurant)
-project level (whos my boss, what am i supposed to be working on)