We have a whole philosophy section and yet all we seem to discuss is religion.
And I use the word discuss really thinly here.
I'd like to refer you to a page that perhaps we should all read before we engage in philosophical debate:
Guide to the Study of Philosophy
I think these beginning points are useful.
As for topics, well, there are millions of questions:
What is the mind?
Are men and women different?
Is there life on other planets?
What is love?
Can you ever understand others completely?
How does language develop, occur and work?
Are animals sentient?
What is truth and does it exist?
How do you know what you know?
All of these are great topics for discussion.