AIDE is a stand-alone GUI prototyping tool, centered around the Window/Event Diagram notation (WED). It takes hand-drawn sketches and converts them into HTML5-mockups, allowing users to add rich transitions between UI parts.
You can watch a little video about how AIDE is used on YouTube. You can also run some deployed demos. For instance, you can look at a sample library management app for smartphone on your mobile device, or a mock-up of a desktop application to be run in a regular browser. More demos to be run in a browser on a desktop machine and to be run in the Mozilla XulRunner are in preparation.
There is effectively no installation of AIDE - there is just a JAR-file. So, all you need is a recent JVM installation with paths set correctly, and that is it. To launch AIDE, just run the JAR, which usually means clicking on it.
Latest version 2.6, last update 2014-04-10
AIDE is a java application, so it should run on all major platforms. It has only been tested on Windows XP and W7, though, so no guarantees are given for MAC OS and Linux.