This page is a list of links to external JavaScript projects which could be potentially ported for use as bananas.
Markdown: Showdown
Textile: this one is GPL, same for this one, however this one isn't marked, Jeff Minard who improved it off Stuart Langridge seam to have released it as PD.
json-template: http://json-template.googlecode.com/svn/trunk/doc/Introducing-JSON-Template.html
natural sorting: http://sourcefrog.net/projects/natsort/ (The actual JS version looks real bad... But how it weights things could be used with a quick .scan and .reduce to create a powerful sorting function)