JSitor - Test your NodeJS, JavaScript, CSS, HTML online with JSitor code editor.
Toggl - Toggl is an online time tracking tool. It features 1-click time tracking and helps you see where your time goes. Free and paid versions are available.
JS Bin - Sample of the bin:
Harvest - Simple time tracking, fast online invoicing, and powerful reporting software. Simplify employee timesheets and billing. Get started for free.
CodePen - A front end web development playground.
RescueTime - Time management software that shows you how you spend your time & provides tools to help you be more productive.