Garry's Mod requires only that you have one Source game.
This includes Half-Life 2, Half-Life 2 Episode One, Half-Life 2 Episode Two, Team Fortress 2, Counter-Strike: Source, Half-Life: Source, Portal, and a few others.
However, if you have Half-Life 2 Episode One, you will only be able to experience Half-Life 2 Episode One (and Garry's Mod) content. You won't be able to fight alongside Griggs and Sheckley with a home-made "Antlion Dispatcher", or be teased with cake while solving complex puzzles using the portal gun, physgun and toolgun.
Long answer short, you should only need Half-life 2 Episode One in order to play Garry's Mod, but you can experience more of Valve's games in Garry's Mod if you have all of Half-Life 2.
Garry's Mod has now updated and includes all features of 13 Beta
All steam games update themselves automatically.
For the half lives of all curium isotopes see the link below.
From what I've gathered, there WAS an episode, but they decided to cancel it because it was clearly a fanservice-based episode.
yes and then you can give a hobo a penny and he will give you a free plasmascreen!!!
Yes, garry's mod will work with portal and you will have all the HL2 stuff.
http://video.filestube.com/ has them all, just search for them ;)
Not necessarily. If you own absolutely no Source games at all, then you can buy it, and you can then run Garry's Mod. A lot of Garry's Mod addons require Counter-Strike Source though, so it's recommended, not required.
Go to wikapidia, and it has every episode from every season. i just cant find the description for all of them!
Garrys Mod 10 Is available on Steam, Which can be found at SteamPowered.com You First need to get a Source Game, which can also be found on Steam, that is including Counter Strike: Source. All and all it should cost about 21 US Dollars.
The second episode was "big time school of rocque" and if you want to know all of them in order just google big time rush episode list
Just type in google House Of Anubis episode 8 tv-links. You can watch all the episodes there :)