You can download flash games and take them with you so that you can play them on any computer, even those that are blocked at work or school. Go to site that has the flash game you want. When you get to the page with the game on it, go to File -> Save Page As... in your browser and save the page to a location on your desktop. This will create a .html and a directory. where the name of the file and the directory will probably be the name of the page.

Once you have these files on your desktop, insert a flash drive in your computer and copy the file and the directory over to them. You can now take this flash drive with you, plug it into any computer, and click on the .html file to start playing the flash game.