Org-mode is a powerful system for organizing your complex life with simple plain-text files. It seamlessly integrates all your notes, mindmaps, TODO lists, calendar, day planner, and project schedules into a single system that can be easily searched (e.g. by grep), encrypted (e.g. by GnuPG), backed up and synced, imported/exported, and accessed on the go (e.g. on an iPhone or Android smartphone).