You can't as far as i know. at least not legally. you'll need to buy the full game.
Y is there a xbox 360 garrys mod
Yes, and it's fun and free.
No you need the full game or any other source engine
no, not unless you make the map your self an then invite friends to your party
Blue Angels A Year in the Life - 2005 The Demo 1-2 was released on: USA: 2005
Yes you have half an houe before you have to start again.
Half-Life, Half-Life: Blueshift, Half-life: Opposing Force, Half-life: High Definition pack (might not classify as a game), Half-Life: Source, Half-Life 2, Half-Life 2: Episode 1, and Half-Life 2: Episode 2. Eight games total not including countless mods created by fans that you can download for free on moddb.com and fileplanet.com. Other games by Valve software include Left 4 Dead, Left 4 Dead 2, Portal, Portal 2, Counter Strike, Counter Strike: Source, Team Fortress, Team Fortress 2, and Alien Swarm. Another Half-Life game would be Half-Life: Decay. You might also be able to count Half-Life Deathmatch and Half-Life 2 Deathmatch.
you start with half life 2, then you play half life 2 episode 1, then you play half life 2 episode 2, so you are basically playing them in the order they are in at the game select screen (where you choose any of the half life games, portal or tf2)
No, only Half-Life and Half-Life: Decay.
Half Life 2 Half Life 2: Episode 1 Half Life 2: Episode 2 Portal Team Fortress Hope this helps ;)
there is a demo for mafia 2 you can download it in steam
Buy Half Life: Source Or Buy Garrysmod a Half-Life 2 Modification and get the addon "Half-Life Rennaisance" Link to Half Life Rennaisance: http://www.garrysmod.org/downloads/?a=view&id=57033 Enjoy!