The Two-Layered GUI Toolkit is a library of GUI helper classes which is designed in a way to simplify development of separate interchangeable front-ends. For every supported dialog box type, there is a settings class (independent from a GUI toolkit) whose options can be used by one of the implementations for a specific GUI toolkit (bindings for Gtk#, WPF, and WinForms are provided, but custom ones can be added). That is, the dialog definition can be prepared by the application's core component and passed to the front-end, which uses it to instantiate the dialog box using whatever GUI toolkit it likes.
Wieldy is a to-do list manager that is based on the principles of GTD (Getting Things Done). It allows you to manage your to-dos in a simple but effective way. To-dos can be created as thoughts and actions, which can then be assigned to the Next Action, Today, or Someday categories. Tasks can also be scheduled and listed in a calender-like overview, as well as linked to a project or simply put on hold. Wieldy also allows you to manage your contacts and delegate actions to them. Other features include support for data encryption, tagging, priorities, recurring action templates, and synchronization with other PIMs like Outlook. No installation is needed.