Card sort for browser

We need a web site (browser based) application that can run locally or across the web. It needs to allow the user to sort - drag/drop "cards" into piles/lists. There would be around 50 cards to sort (although we may have to change the the wording on these so need to be able to do that ourselves. Each card would have a heading, and then a couple of paragraphs of text. once they have sorted their cards, they need to be able to save the file and re-load later.