This is my favorite mod of all time you only need HL2 or Portal. It\'s more awesome the more you play it. I am only 13 years old. It took me 2 years to customize it.
No More Room in Hell is a free to play Half-Life 2 mod. It's a multiplayer, 8 player co-op survival horror game with a focus on semi-realism. It was inspired by the "Of The Dead" zombie franchise which is where it gets its namesake.
This mod is all about having fun. There are no scores, goals, etc. You are given a random situation, some tools, and then let loose to enjoy the fun aspect of just screwing around. This mod is more of a collection of mini-games you can play.