
*click on the image for a cool video
http://tesseract.gg/It's like Quake! No, it's like Minecraft! No, it actually doesn't look like stuff!
You can edit with other people in real time. It uses cubes and stuff but you can edit the cubes and add world models and stuff. Pretty fun. Based off the old Cube 2 engine but it's a modern update with HDR and real-time shadows, volumetric lighting, and all of that stuff. It's open source and free too.
I'm not able to host but hey, whatever.