a tool-kit for creating "web 2.5 generation", include several useful stuff to work with semantic web (otology editor, gui for sparql query, ontology components...) and design RIAs's gui visually (html + ajax based apps, flash based apps,...)
The PyQt4D (Python Qt for Designer) is an Open Source Project making Qt Designer full-featured RAD (Rapid Application Development) tool to develop data-aware two- or multi-tier applications using Python language and Qt library.
Oh my God i`ts movin - is the Linux only tool for creating animated PNGS. omGim alows you to easilly create and edit existing apng`s with help of GIMP or Inkscape. You can import frames from PNG, SVG, etc.