Valve World - Fan made crossover of all Valve games

Who do you think would win in a Valve Battle Royale? Find out!

Portal fans... your turn!

Just a real life steampunk version of the portal gun dedicated to the Portal game series made by Valve.

Left 4 Dead 2 / Portal 2 - Amazing Easter Egg - Must See!

In this video MasterOfAudioSurf showcases this mind blowing crossover Easter egg of Portal 2 and Left 4 Dead 2 from the addon campaign of Suicide Blitz.

To download the addon campaign:
http://www.l4dmaps.com/details.php?file=9754

Portal / Half Life - Crossover - Conspiracy theory - FANS MUST SEE THIS!

I am a big fan of the Half-life / Portal universe, but as everybody, I am curios what will happen in Half-life 3 / Portal 3. After hours browsing on the internet I found this video the most logical explanation that sets up a crossover game for Portal and Half-life sometime around 2013-2014.

http://www.youtube.com/user/RightHandARama

Now that is what I call walkthrough!