Online book club. I personally love a book club. Have mods to pick the books, political, historical, witty, fun, religious, theological (within reason), etc. Anyone who wants to can discuss. Unlike real life book clubs, people won't feel pressured to read every one, they can do the ones they want and skip others. I would advice that you don't pick any grossly irreligious books, because even though discussing these can be good apologetic practice, it would turn some people off as a "focus." Also, (hence the mods) no books with blasphemy, overt sexual content, etc. The nice thing about this as well is that the book would be introduced, a timeline for reading would be issued, and a discussion begun. After so long you shut it down and start the next book. No dusty threads.