Hourglass - Hourglass is the most advanced simple countdown timer for Windows.
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.
TIMEBOX - An advanced timer for professional meeting facilitators
Harvest - Simple time tracking, fast online invoicing, and powerful reporting software. Simplify employee timesheets and billing. Get started for free.
Online Alarm Kur - Free online alarm clock, set alarm easily on your computer using the internet alarm clock without downloading any software, wake up in time with the loud online alarm clock.
RescueTime - Time management software that shows you how you spend your time & provides tools to help you be more productive.