My girlfriend is talking about getting a Minecraft server, which I would administer. I don't really want to play online unless it's my server or being run by someone I know personally. Don't like the idea of investing a bunch of time on some random server that could go down at any moment, you know?
Oh, and I'm still working on my castle footprint in my SP World 4. Dug deep enough to find gold. Also hit a couple caves, which I sealed off and left small entrances for (so I can get to them later.) I think I'm about halfway (or more) to the bedrock.