Best Free Timer and Alarm Clock

Introduction
Lots of people use their computer for almost anything. So why not use it as an alarm clock, waking you up from your dreams? And what about reminding you to go for an appointment right away before it's too late while being engrossed in something else on a computer?

There are lots of alarm clocks on the internet, but most of them don't wake your computer from standby or hibernation. Why leave your computer running all night just for one important task: to wake you up?!

These are freeware programs which might be useful and interesting to you if you don't like that waste of energy either.
Discussion


WakeupOnStandBy, like the name already says, it wakes your computer from standby or hibernation. You can set this program to run whatever you want after it wakes up. It's also possible to set it for different time schedules, using multiple instances of the program.
You could use it as an alarm clock by starting up internet radio or m3u-playlists. It works nicely in combination with another one of the developer's free tools, called Toff, which puts your system to sleep.

Alarm Clock of Justice is a computer alarm clock that can wake your computer from standby or hibernation to play a customized alarm. This includes any file type.
The program has a customizable snooze as well as a standard activated, volume-level control.
Not all soundcards support this volume control though, so you should test if your card supports it or you have to turn this option off.
Simple Alarm Clock, a really simple version from the same developer that just does what it's supposed to: Waking from standby/hibernation and running the file you want.

Free Alarm Clock has a clean and simple user interface, combined with useful functions such as loop and snooze, repeat alarm, wake up the computer from a sleep mode, turn on monitor power and adjustable volume.
You can set as many alarms as you need, choose the sound for each alarm, label it and indicate in the text field the activities you need to do at the times you set.

This program has a portable version. You can download the zip file, extract it to a folder and run it right away without the need to install. All your settings are saved to this file Data.ini in the same folder.

Other alarm clocks (without waking from standby):
Marxio Timer "Program executes action specified by user (turn off, restart computer, hibernate, suspend, logout user, lock desktop, display text, play sound, run other application). It's run at time specified or when idle time elapses. It can also repeat actions after n minutes or start countdown seconds to execute action."
Note: The vendor's own download location is now offline. I checked the Softpedia link and this was still working as of 30th of December 2012.
Karen's Alarm Clock: Turn your $2,000 computer into a $20 alarm clock! Set up to five different alarm times. Wake up to a beep, any wave or MIDI file, even a track from your favorite audio CD. Great for travellers, or the executive who likes to sleep on the job. :)
Cool Timer: Simple, no-nonsense, handy timer utility with cool, customizable interface.
*Alarm Clock 1.0: It's an alarm clock for your PC, with a total of eight alarms--one for each day of the week, as well as an additional one-time alarm for use at any time. You can use the built-in sound (very obnoxious) or you can even have it play MP3s.
*Warning: Downloads from Cnet (Download.com) now require the use of a proprietary installer.
Talking Alarm Clock: lets your computer remind you of important dates and events. It uses Microsoft? Agent to show a talking animated alarm. The alarm can also play any sound you choose and includes a handy snooze button.
Alarm Clock by Tarry91: "Alarm Clock by Tarry91" is a professional alarm clock that does not require installation. You can configure multiple alarm events including recurring alarm and optionally launch a file or MP3 song when the time is up. Other features include a choice of GUI color, customizable alert messages and system tray support. No installation needed, copy the *.exe file to a folder of your choice.
Kukuklok: Kukuklok is an online alarm clock. It is free and has an unbelievable user friendly interface.
Kukuklok offers five different, very efficient alarm sounds, which guarantees that at least one of them will wake you up. It is really easy to set your time. Simply use the arrows to choose an hour and minute.
The clock is in 24 hour format, so you know when the alarm is going to sound. Another great feature is that the time is in your computer time, not the server time. Also, if your internet connection goes down, no worries, your alarm will still go off.

Source:  http://www.techsupportalert.com/content/best-free-timer-alarm-clock.htm