Some current news topics can provide a good basis for a discussion. Always try to see what God is saying about a particular issue, or what our response as Christians should be. This kind of discussion regularly leads into prayer for the situation, or into an idea of how the group can help practically. Both local and international issues may be suitable for this type of discussion. It is good for growth of the group if the topics are relevant to the work of the organisation.
Avoid approaching issues from a political perspective. Focus on what may be happening in the spiritual realm, what God is doing, and how God is calling us to respond.