1) Tell me your life story.
2) Dating and romance (even works with older married students, or uni-aged students who are too young to have dated).

Love vs Study

Gangs: Bloods, Crips, Hell's Angels, Triads...differences and why it's not worth your life to join one.

I try to keep up with pop culture and ask them about Fei Chang Hu Rao, Sister FengFeng, Guo MeiMei, whatever is going viral at the moment.

Also, Occupy Wall Street and the rigged Russian elections have got them asking about protests. I've told them about the Velvet Revolution in Czeckoslavakia 1989 and May 1968 in France. That was thier first time hearing about those. There were some that happened in China too.....

I had a student want to discuss sex before marriage... I think she was a first year too (at university, you perves!)

I also think that many people here are quite aware of many social problems here, but usually don't feel confident in discussing them openly in a normal gathering, but having a foreigner can break that shyness. They want to talk about things, but aren't sure. It's not a topic I tend to bring up, but if they do, I won't shy away from it.

If it's an English corner at university, discuss their ways to fix problems, or come up with something controversial, and act as mediator or devil's advocate. It gets them really wanting to say something...

This website has a lot of ideas. http://englishlessonsforchinese.com/