todo.txt is a simple way to keep track of what you’re doing in a single text file that can be read by any text editor. There are also front-ends that can be installed on your phone and computer.

(A) 2016-02-16 Plant roses @outside +garden due:2016-02-17

  • (A) - Priority for the task
  • 2016-02-16 - Date the task was created
  • Plant roses - Task description
  • @laptop - Context for the task
  • +garden - Project the task is assigned to
  • due:2016-02-17 - Due date for the task

There’s for Windows and Simpletask for Android that can sync the task file using Dropbox.