No matter how much the desktop gaming industry progresses in terms of graphics, game play and overal user experience. The highest level of addiction still lies in the light-weight online flash games. For some people, online games are just a passtime to fill in hours at office or at lunch time. For others, online games are a hobby that keeps them addicted to the computer for hours and hours.
These games vary from simple one-click mouse games to the ones with advanced gameplay using a keyboard. I have put together a list of the MOST ADDICTING, REALLY ADDICTING, INSANELY ADDICTING online games ever made since 2000.
All these games have been actually played for atleast a month, tested for addiction and then posted here. Have fun and put your high scores in the comment box at the bottom 
1. Desktop Tower Defense
Desktop Tower Defense is a fun puzzle / strategy game where you have to protect your desktop from invaders by spending money on attacking pieces and building a maze for them to follow. Creeps enter from the top and from the left. You must stop them from reaching the other side or you will lose lives. You start with 20 lives, and when they are gone the game is over.
Name: Desktop Tower Defense
Type: Strategy / Puzzle
2. Monkey Kick Off
Monkey has gone football crazy, so get those Monkey feet in tip top shape and kick your way to the Monkey Village where all your Monkey friends will be waiting to welcome the longest kicks home! Monkey Kick Off is an extremely addictive game, specially when you have been challenged by your friend and have to beat his high score.
It’s all about laws of physics. Think speed and angle for monster kicks. May the best monkey win!
Name: Monkey Kick Off
Type: Adventure / Physics
3. Crazy Taxi
Crazy Taxi is a silly but addictive game. You have to drive the taxi using the maximum possible speed. This game is also available on facebook as an application, where you can challenge your friend’s high scores and try to beat them all day.
Name: Crazy Taxi
Type: Arcade
4. WinterBells
WinterBells is a very fun game with a simple game play. The cute little rabbit has to jump on the bells to go as far on top as possible. All you have to do is move your mouse right and left to make the rabbit reach the bells.
Name: WinterBells
Type: Arcade
5. Avoider
Avoider is a very unique and creative game. It keeps you addicted for hours. The cute sumo-like guy tries to catch your mouse with different strategies. He can fly, load missiles and play other tactics to do that. Your goal is to protect your mouse cursor.
Note: This is a japanese game so you will have to click the first button to start the game.
Name: Avoider
Type: Adventure / Arcade
6. The Shell Game
The shell game is very popular. Like you may have seen in casinoes, the ball is hidden under a shell and shells are moved quickly. You have to keep your eye on the shell with the ball.
Name: The Shell Game
Type: Arcade
7. Double Wires
The best ever spiderman game yet! This is such an addictive game where you have to save the swinging man (who seems to be drunk) from falling down. Each click throws the rope towards the line and pulls the man forward.
Name: Double Wires
Type: Point’n'Click
8. Chim Game
This is one cute and funny game. There’s a pottty man on top and you have to save the baby from him. The baby also fires something towards the man.
Name: Chim Game
Type: Arcade
9. The World’s Hardest Game
The world’s hardest game (or so they say) is very addictive, but not so hard if you get hang of the game play.
Name: The World’s Hardest Game
Type: Arcade
10. Helicopter Game
Helicopter game is an addictive game in which you have to keep the helicopter moving forward.
Name: Helicopter Game
Type: Arcade
Don’t get fired!
More addictive games coming soon…
I have beaten your score in monkey kickoff! 5451!!