Friends here's a trick to download your Favourite Online Flash Game and to play it offline. 

Just follow the simple steps mentioned below.

First of all you will need a Download Manager which you can download from here.

Also, you will need a Flash/SWF Player to play the game, click here to download.

Steps:

1. Go to the page with Flash Game that you want to download.

2. Let the page to load completely.

3. Right click on the left/right side of the page and click on View Page Source (For Mozilla).

4. Press Ctrl + F and search for .swf.

5. Then select that link (for e.g http://www.playhub.com/swf/dummy-never-fails-c.swf).
6. Paste it in Add URL option in your Download Manager and start download.

7. Now you can play that game in your Flash/SWF Player.

8. Enjoy :).

Few Sites to Play Online Flash Games :

1. Playhub

2. GamesFreak

3. GamesPortal

4. MiniClip

If you are finding difficulty in this process, Reply to this post.