This guide will cover all the possible ways to play steam games for free
Before starting, make sure you will use any blank account (make a new one) and not your LEGIT steam account.
This content will be updated every time a new method is out.
New Method - Updated February 14
(All the old methods are removed)
This method will show you how to download the most games from Steam. First you need the latest steam client.Get it from steam's site.
Now before start, you need to know the games you can download with cracked steam client. Counter-Strike Source (Needs Mini-GCF)
Half-Life 2 Deathmatch
Team Fortress Classic (Needs Half-Life)
Deathmatch Classic (Needs Half-Life)
Ricochet (Needs Half-Life)
Day of Defeat (Needs Half-Life)
Day of Defeat Source
Rag Doll Kung Fu
Poker Superstars II
All PopCap Games
Here is a trick based on a steam's bug to get some other games like Half-Life 2, Gumboy Crazy Features, Zen of Sudoku, Dark Messiah of Might and Magic (Singleplayer).
Install the Steam client and let it to update. Log in into your account (a blank) and let it to update again. Now from main menu, click on store and select the demos from find more (on the right). Select a game would you like to try (there is not any way to get all the games, you should try first).
On the next page, click to install the game
When finish, select to open steam my games list (so you can track the dl progress).
As you can see, the demo starting to download (no servers error of course).
Now close the steam client and apply the patch from this post (attached to post).Keep the original files (backup).
Now reopen the steam. You will see the Full Versions of this Games in the Gamelist under "Installed".
Then you just have to update this Games so they become the Full Version.
So when you finish, you should have the full game content.
For The Steam servers are currently too busy error, the best method is to have the full GCF's in steamapps folder and the game must be 100%.
How to patch the client
First delete all the contents from your Steam folder.Install and let it update.Login and let it update again.Now get the patch and steam.cfg files (attached to the link above). Copy Patch and Steam.cfg into your Steam Directory and execute the patcher.
When a new Steam update is out, rename the Steam.cfg to Steam.cfg.old (or whatever you want).
Now let steam Update. After its updated rename back the Steam.cfg.old to Steam.cfg and execute the patch again.