TaskTXT is a unique text-based task-timing notepad app which I designed. TaskTXT is an evolution of my personal strategies for managing time and attention. It uses a novel method of storing app state within the user-editable text. Try it at TaskTXT.com.
TaskTXT uses freeform pages to naturally capture tasks. A timer and checkbox magically appear next to each task. Enter an optional guess for how long a task will take. Starting a timer when you start working on a task is a great way to increase focus and avoid distraction.
For more on text-based software, the research lab Ink & Switch published a paper, Potluck: Dynamic documents as personal software, which makes reference to TaskTXT.