jEdit is an open source text editor; has many useful features, such as syntax highlighting, bracket matching, regular expression searching, multiple file search and replace, folding, and keyboard macros.
TuxPaint is a simple and entertaining drawing program geared towards young children; with a simple interface, sound effects, and a cartoon character (Tux, the Linux penguin).
WikkaWiki is an easily customizable wiki which allows effortless management of web sites and their content; it features W3 compliant XHTML and CSS output.
jPOS is an openly developed framework that can be used to implement financial interchanges, protocol converters, payment gateways, credit card verification clients and servers (merchant/issuer/acquirer), etc.
