How to see ghosts or surely bring them to you

Historical Caterina is even more awesome! Check out http://en.wikipedia.org/wiki/Caterina_Sforza .Her last confession went something like 'If I wewre to tell the story of my life, it would shock the world' although to be fair that probably wasn't hard to do in them days. And it's not as good as Marco Polo's, which went 'I did not tell half of what I saw,' to a priest who wanted him to confess that he was a dirty rotten liar.
God I love history.