Microcal is a small, embeddable PHP calendar script which works in a pop-up mode, as a standalone script, and as an inline calendar.
Pyrostia is a weekly menu planner. It allows adding meals and recipes in a weekly calendar and automatically parses ingredients for storing in a weekly grocery list.
RoCanvas is a small and easy-to-embed HTML5 drawing board component. With some server-side programming, it can be used to save drawings to the server, create galleries and contests, let users draw their avatars, etc.
A database developer IDE.
A job dispatching server.