Failing that, just write topics on pieces of paper, put them in a bag and get them to pull the bits of paper out and discuss. As soon as it's clear that they're bored or they really have nothing to say, fine, it's time for the next piece of paper.
I found with a 14 year old student that getting him to use his imagination always helped. I asked him, for example "If you could have any superpower in the world, what would it be, and why?" and "Imagine that you are any character from history or fiction and as that character, you are president of the world! What changes would you make?"
As an aside, as this forum is read by students and teachers alike, it's important that the teachers stick with correct written English at all times so that students don't pick up bad habits. That's why I made some corrections in red to your post. We discourage any kind of textspeak so please try to avoid "wanna", "gonna" etc. Thanks.
- For Teachers