Grasshopper wrote:James Randi offers (and has done for a long time) a one-million-dollar prize

Yes, of course it does.
Grasshopper wrote: engage in daft conversations like "he doesn't like the new picture in the hall" type affair, instead of asking the dead questions like " can you see the whole universe? What's if like?"
Just to let you know, I'm very much on the fence when it comes to psychic phenomena. As a magician I know only too well how such phenomena can be reproduced using conjuring techniques (heaven knows I've done it often enough myself). On the other hand I have witnessed too many weird things in my time to dismiss everything as superstition, mumbo jumbo, or (god help us) flim flam.
The reason mediums tend to concentrate on such seemingly banal things like the spirit not liking the picture on the wall is because this provides personal proof to the sitter that the medium is indeed chanelling the spirit of their deceased relative. ie how would the medium know about the picture?
If however the medium went into a long poetical rant about how the spirit was in heaven, and could see beautiful lights stretching as far as the edge of the universe etc. etc., then such a message from the spirit could never be verified. It means absolutely nothing to the sitter. It contains no personal info and the medium could very well be simply making it up on the spot.
That is why the medium (whether he be in communication with a spirit or be using reading techniques) concentrates on what at first glance may appear to be banal or trivial information. In fact personal information is anything but trivial. It means the world (and more) to the sitter.