FreeMarker sketchbook

FreeMarker sketchbook is a quite polished (especially for a "0.1" release!) online playground for exploring FreeMarker. It's a JLNP application, and it launches into a Swing application with a tabbed window with tabs containg the full FreeMarker manual, a sample data model, an editor for the template, a HTML viewer for the output, and a HTML source viewer for the output.

Neat!