Taskful - Deadlines, meet your match.
T-Clock Redux - T-Clock Redux in an enhanced fork of Stoic Joker's T-Clock 2010 with ISO week number support...
Calendarist - Time blocking companion for Google Calendar
DS Clock - Keep your time synchronized with Atomic Time servers, using customizable digital desktop clock with westminster chimes.
Centered - Centered helps you get into a Flow State faster and stay there longer so you can do your best work.
AlarmDJ - Online Alarm Clock - Use YouTube videos or MP3 files as alarm sound. Works offline.