When you have graphs to draw or statistical concepts to teach, you need your data and you need it now. You can look for a suitable dataset, or you can simulate a result, but that can be annoyingly tedious. DrawMyData by Robert Grant is a simple tool that lets you click an x-y plot to draw points, and then you can just download the the x-y coordinates as a CSV file.
Tools like this always seem kind of frivolous at first, but then you use it a few times and becomes indispensable. [via @albertocairo]