Alive: Jesus (the Bible says he rose from the dead, and is coming back one day). Why? Well, he's amazing company, full of great stories, wisdom, and if you run out of booze, no problem. Just give him some water and leave him to do the rest.

Dead: Oscar Wilde. Plenty of witty conversation would ensue.

Fictional: Mary Poppins. We could have dinner on the ceiling, and I want to jump into some chalk drawings after dinner.