Here are two really cool flicks from BMW films.
For those of you who may be curious, this is a chart of Air Force officer rank insignia and also the Royal British Air Force equivalents. During the 10 months I spent at IBM as an intern, I spent as much time explaining what a captain was as I did working on projects. I am presently a captain who's been selected for promotion to major. That's really great, but I'm going to have to wait about 18 months before I can put the rank on and enjoy the commensurate pay raise. That sucks, but things could be a lot worse.
Here's an explanation of the rank insignia I heard in basic training.
All entry level officers are second lieutenants, except for in the Navy where they're called Ensigns. Second Lieutenants wear a single gold bar because the metal gold is deep underground and it is very soft. Second Lieutenants are very young and malleable.
The 1st Lieutenant wears a single silver bar because silver is a stronger metal and it is found closer to the surface. 1st Lieutenants have two or three years under their belts and they have some master of the fundamentals of being an officer and leader.
A captain wears two silver bars joined together to show their strength in the fundamentals of officership. It's a sort of "master's degree". You're expected to know your craft when you become a captain.
Major is first rank where a person can become a commander. Consequently, majors are looked upon as being very inexperienced in the ways of being a commander and again very malleable. The oak tree is a very strong wood that grows above gold and silver, who's roots run very deep a broad. A major wears a cluster of gold oak leaves to symbolize their youth as a commander. Major is also the rank where an officer starts to build his/her breadth of experience as an officer (e.g. get experience in other disciplines).
Lieutenant Colonels wear silver oak leaf clusters to symbolize their mastery of the skills of being a commander and their strength as a leader.
Colonels wear silver eagles. Eagles fly above the trees and the ground and they have the ability to cover the sky. Colonel is looked upon as the transcendent rank between being a "regular" officer and a general. For the everyday troop, when a colonel speaks, it's almost like hearing the voice of Archangel Gabriel.
Generals wear silver stars. Stars sit above the sky and the ground and silver again symbolizes strength. The more stars you have, the more of the heavens you can encompass. Hence the four general officer ranks. Also, the name "general" itself is very symbolic. The higher you go, the less specialized you become or the more "general" your job gets. One, two, and three star generals are still attached to a specialty (e.g. transportation, communications, human resources, etc.). Four star generals or "Generals" are expected to be able to manage the entire range of speciaties that fall under they're purview. They are true "generals".