Yeah anything controversial. Maybe a question like "Why are men/women so lazy?" "I just got mugged" "My girlfriends cheating on my with my son, I saw them in the garage"
So I make a forum for people to discuss about "Why are men/women so lazy". so they will register and talk about it? So far I like the money one the most.
I would say the most popular topic is the current issue hot at your country such as new law implemented. Let user express their view on the matter.