T-Clock Redux - T-Clock Redux in an enhanced fork of Stoic Joker's T-Clock 2010 with ISO week number support...

Taskful - Deadlines, meet your match.

ClocX - ClocX - freeware analog clock for Windows desktop with many features like calendar, alarms, skins, antialiasing and transparency.

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.