Break time on your office is supposed to be the time to refresh your brain. You can take food to fill your empty stomach, you can sit down and relax, and if you still have little more time you can Play Free Online Games. It will give you fun time and happy feeling to bring good mood.
Free online game can be play from your computer without installing new software to your computer. Even strategy games such as Tower Defense Games do not require you to download software. Many browsers support the site and the game. Flash player is needed, but commonly every computer has flash player installed, so no problem at all. You only need to click the game, play it, and shut it down when you finish. It will not disturbing your computer system. You can continue using your computer for work after the break.
Since it is your break time for work, you may only have limited time to play the game. Classic Games is recommended, but not with strategy games. Strategy games is not fast game because you need to build something, make this and that, and many other thing you need to do to win the game.