Garry's Mod
 

Anyone else play this?
I usually play the following:
Zombie Survival
Super Mario Boxes
Retro Teamplay
Others like to play Roleplay, but I dislike Roleplay. The only kind of roleplay I kinda like is PERP, which stands for Pulsar Effect Role Play. But as for sandbox, I am usually just good at making things that look nice, but not really that great at mechanical stuff, and I can't do anything with wire/E2. I also have several mods for my singleplayer, such as Pokemon Models and a bunch of entities, for example Quantum Storage Device. (Just a quick reminder for mods, a lot of mods go into program files/steam/yourusername/steamapps/garrysmod/garrysmod/addons.) For those who are wondering, it's a multiplayer sandbox game that you can only get on steam, nowhere else. It's mainly focused around multiplayer, but of course singleplayer is still an option.