The Lounge is place to relax and have a little fun. It's not the right forum for fighting (that's the Dome), discussing politics (that's the political forums), or religion threads (that's GD with a REL tag in the title).
What fits in the Lounge? Funny threads, lolcat pics, your home improvement projects, threads on books, movies, music, or recreation, news of the weird or the bizarre, animal info, fashion, quiz and puzzle threads, trivia, funny polls, and anything that is amusing, or informational in a lighthearted way.
What doesn't fit in the Lounge? Naked pics, porn, heated arguments, any kind of politics unless the humor is completely nonpartisan, serious threats, seductions, or backstabbing, or anything else that is highly contentious. As with all other parts of CU, posting PMs without the explicit permission of the other party is absolutely forbidden. It will get you kicked out of the Lounge and possibly off the site.