Gone - An ephemeral to-do list
Taskful - Deadlines, meet your match.
Todoist - Todoist is a to-do list that helps you get organized, at work and in life.
Centered - Centered helps you get into a Flow State faster and stay there longer so you can do your best work.
Check - Check is a unit testing framework for C, which runs on environments such as GNU/Linux, GNU/Hurd, BSD, and Mac OSX.
Calendarist - Time blocking companion for Google Calendar