I said yes...as in I believe fantastic things can happen that we can not explain away with our scientific knowledge or knowledge of natural phenomena.
It may be that there is a perfectly logical explaination (and we may discover that as our understanding of science grows) or there may be an omnipotent being who can pull their finger out from time to time and make great things happen....although it begs the question, if he/she can do that, why does he/she allow so much pain and suffering for millions of innocent people?
I have never seen or experienced a 'biblical' style miracle. I have heard stories second hand though...one that sticks is a girl who was terminally ill with leukemia. She went to Lourdes and was convinced she was going to get better. Three months after her trip to Lourdes she was in remission. I don't know if this story actually happened, it was certainly told to me by a very genuine person who seemed to believe it. If it did happen then there could be a perfectly logical explaination (that we yet don't have the knowledge to comprehend) or God intervened and made her well.