Pieces of Paper
Once Swami Vivekananda was in Kashi with a few friends, devotees and disciples. One of them, who was clearly unimpressed with what he saw as mere philosophical talk, kept repeating that those ancient mystics of India who had access to supernatural powers and abilities known as siddhis are no where to be found these days. Vivekananda did not comment. The next day when the group arrived to meet him, they found Vivekananda with a pile of small, folded chits of paper.
He asked each of them pick one piece of paper from the pile and keep it with them. Then he told them to ask him any question about themselves whose answer he has no way of knowing. Once the questions were asked Vivekanada told them to open the chits they had picked and check what is written there. To their complete amazement each one of the individual pieces of paper contained the exact and correct answer to the question they had asked!