Outliner Lighto is a console-based outliner/hierarchical editor. An outliner is used to edit an hierarchy of text (a tree with text in every node). This hierarchy can represent anything the user wants, like TODO lists, calendar, tasks, address book, bookmarks, etc. It is based on FreePascal's video and keyboard units.
headstak is a stack-based task list. Before you start a task, or when you are interrupted while working on a task, you push the current job onto a stack. When the interruption finishes, or when the task is complete, you pop it from the stack - leaving you facing the job you were working on beforehand at the top of the stack. Run it and it should appear on your status bar as a little stack of stuff on a head. It is activated with the Control-Command-0 global hotkey.