Task management, at times, gets so complex that you need a better way to keep track of the things you have to get done, other than just taking a mental note of them. Not doubting the use of a stack of Post-it notes, but you might want to use a more sophisticated method for creating lengthier to-do lists or reminders. Nitro is a free Mac app that lets you do just that. Besides an aesthetically pleasing interface, the app is very well written in terms of functionality. Tasks can be grouped into lists, you can set a due date for a task and add tags and notes to it. It supports keyboard shortcuts, allows you to control how the week and date are laid out, comes loaded with five UI skins to chose from and last but not the least, syncs with Dropbox and Ubuntu One.