I have been working at UN for almost a month now and I am currently a member of DOC and DOM. However, I have joined DOF and DOE last year when I was working at UN and I think I understand the goals of all the Departments of UN. For those who don't know what these departments do or know what they are, this thread is for you!
Departments:
1) Department of Events. Ah yes, the first department I joined and left. DOE is the department which hosts events either about typing (Shout It Out, Fastest Typer, Trivia, World Capitals, etc.) or about action (Fridge Game, Balloon Game, The Mole, etc. The goal of this department is to benefit the host and the participants since the participants get rank points whenever they participate or win a round while the host can complete their minimum by hosting games.
2) Department of Forums. The second department I have joined was DOF and I quite enjoyed it but school had to take it away from me. This department is the one which post forum games/competitions so that the participants have a chance to earn some extra rank points and/or pay points. Like DOE, it benefits the host and participants, but sometimes the competitions attract others to join UN.
3) Department of Radio. One of the departments that I have never joined. This department has a goal of DJing and playing requests from the other members of UN. The music that they play brings entertainment to the people who are tuned in.
4) Department of Media. My 4th and last department (for now). This is the department which advertises UN all around twitter, mentioning it's benefits, wired, rules, fun events, radio, etc. Their goal is to promote UN so more people will join us.
5) Department of Community. My 3rd department and I recommend this department since this department has easy minimums for extra rank points. The goal of this department is to analyze the current status and to find out how they can improve the current status in the future. Like DOM, one of the special tasks is to recruit new members, but in public rooms in Habbo.
6) Department of Suggestions. Another department which I didn't join. The goal of the DOS is to take many siggestions from the other members of UN and they will pick the best suggestions and implement them either in the base or in the rules.
7) <UN> Departments. The final department which I have never joined. This is the only department where you have to be Government+ to join. I personally don't know the goal of this department but I'm assuming that this department takes suggestions for new departments.