Plasmatic is a cross platform multimedia delivery and playback system. While designed primarily for digital signage applications, its flexibility allows for any number of uses.
OriSVG attends to give some help to origami diagrams designers by providing markers, arrows, strokes and preformated diagrams in SVG language, and some Inkscape's plugins and scripts.
PennAve is a dynamic photo gallery software written in Python and designed for use alongside F-Spot. It makes heavy use of XML and XSLT for ease of presentation modification and sharing of information with other users, web sites, and programs.