The Server without a name aka Nameless SMP aka Untitled SMP is a developed survival multiplayer server played by a bunch of awesome youtubers including:

Long Journey: http://www.youtube.com/user/longminecraftjourney
ET's channel: https://www.youtube.com/c/projectmccabe
Ryan's channel: https://www.youtube.com/user/ValiantMC
Flaxenwolf's channel: https://www.youtube.com/user/flxnwolf
Reboot's channel: http://www.youtube.com/lowbootcut
MatHDand3D's channel: http://www.youtube.com/user/HDand3D/
Starwebs's channel: http://www.youtube.com/user/starwebs1
Georgia's channel: https://www.youtube.com/user/Licketyish
Yoyoer's channel: https://www.youtube.com/user/IYoyogamingI
GumballMatt's channel: https://www.youtube.com/channel/UC965CetIH9Eb0kCGJvBPmYQ
Ryan's (Chip's) channel: https://www.youtube.com/user/ItsTotallyViral

Make sure you check out the SMP guide text file that contains the coordinates to all the builds on the server!