NotePlan is dead simple in concept. It opens as a calendar, with a grid showing the current month. Each day-square has a list of that day’s events. So far, it’s just like a regular calendar app. But click on a day and you are taken to the Note view. This is a plain-text sheet with the day’s events listed at the top, above a dividing line. Below that line, you can type anything you like. But if you type things in the right way, then these tasks will be turned into tasks and shown on the calendar. What’s more, just hitting a keyboard shortcut can add any task to your actual calendar, or to your Reminders list… More at Cult of Mac.
I like the look of this.