I would invite based upon certain discussion areas of religion I find interesting . For example, whenever a discussion crops up about the astronomical body count brought about through wars, inquisitions, stonings, terrorist actions all in the name of religion and fanatical bloodthirstiness of religious fundamentalists, 3 names are invariably brought up by religionists in their defence - "Well you athiests are just as bad" they say - "What about all those killed by Stalin, Hitler, and Pol Pot?"
So I would invite those 3 ( on a takeaway basis obviously) and ask them the relevant question in those circumstances; "Did you kill all your millions of victims in the name of atheism?", I would ask, " Or is that contention total ********?"
I would invite Ken Ham, he of the infamous Creationist Museum in Kentucky, with its animatronic dinosaurs with saddles ( proof positive that humans and dinosaurs coexisted), along with Richard Dawkins, to discuss the absurdity of Young Earth Creationism in the light of all the scientific evidence to the contrary.
Carl Sagan, just cos he would be entertaining and proof positive that one can view the universe as endlessly fascinating and majestic,without invoking supernatural supervision.
Behe and Bembski, those ludicrous proponents of Intelligent Design, to relive their famous court defeat during the Kitzmiller vs Dover Area School District, and once again have explained to them by Ken Miller, and just for a laugh Stephen Jay Gould just how preposterous the idea of Irreducible Complexity actually is.
Finally, Salman Rushdie and Mohammed the prophet, just to see if Mohammed would really go fatwah on Rushdies ass. :)