Jmol is a Free, Open Source molecule viewer and editor. It is a collaboratively developed visualization and measurement tool for chemical scientists. Jmol is an active project, and there are new features being added to it on a daily basis. Users are encouraged to modify it to fit their needs and to contribute their changes to the project.
UDIG (User-friendly Desktop Internet GIS) is a spatial data viewer and editor with emphasis on the OpenGIS standards for Internet GIS, the Web Map Server and Web Feature Server standards. It provides a common platform for building spatial applications with open source components.
Treebolic is a suite of programs (an engine, a generator, a browser, and example Web services) whose purpose is to give a hyperbolic rendering of a hierarchy of data. A tree is rendered with nodes and edges but display space is subject to a particular curvature: more space is allocated to the focus node while the parent and children, still in the immediate visual context, appear slightly smaller. The grandparents and grandchildren are still visible but smaller still. Distant nodes gradually disappear towards the disk's border, as though the whole hierarchy were seen through a fish eye lens.
PDFView is a very simple program to view PDF files. on contrast to Preview, the main window will open up maximized, and with the drawer hidden by default. When you toggle the drawer, the main window will resize just enough to show it, and maximize again when you hide it. The zoom level will be as big as possible to make the document fit, making it as easy to read as possible.