I don't mean to advertise here, but if language, "adult content" and so on is as big a problem as it's being made out to be on Minecraft servers, you might want to try an alternative game instead.
Those of us who run Minetest (the open source game/engine) usually very careful about policing the users on our servers, to the point at least that adult discussions are usually not tolerated at all, and coarse language/cursing is usually equally shunned. Sometimes, depending on the server, it's okay to "blur" your curses if they're not directed at someone in an insulting manner.
Some servers have PvP enabled, but I guess most server owners have that turned off.
We're small, and we're not Minecraft, but I think we do okay, and besides - its fun.
Freenode channel #minetest or http://minetest.net/ if you want to take a look. And no, it's not supposed to be a Minecraft clone and it does not use any code or assets from that game. It's just supposed to be similar enough to appeal to same "sandbox" audience.
Full disclosure: I am a modder and texture pack author for this project and have contributed a couple of small things to the engine.