I've taken the time to build a huge castle and city on a server with several other friends. We have fully functional subway system. You walk to the station, push a button for which direction you want to go, push a button to bring the minecar to your location. The car stops in front of you, you get in triggering other electronics to send a booster cart next to you, sending you off in your chosen direction.
You can be freakin brilliant in this game.
My castle had huge keeps on either side of the draw bridge, a big wall all the way around the castle courtyard complete with murder holes, there's a castle in the courtyard complete with dungeon, hidden passages, its own keeps that jet up into the sky higher than the courtyard walls (and all the walls were spider proofed, too). Upon leaving the castle via drawbridge that bridges the gap across the moat (because my castle was built at the center of a big ol' lake

), you find yourself passing two guard houses on either side on the mainland. I have horse stables for my nights complete with farrier workshop, a gallows, a stockade, a village complete with small homes that are fully furnished, a foreman's office and mine entrance, a dock with a harbor master's office and dock warehouses, an actual dock out over the water, a pirate ship moored to the end of the dock complete with working canons that shoot arrows (other projectiles don't do damage), the entire city is surrounded by walls with small keeps periodically...
I could go on and on. It's really neat to be at the max render range on the hill overlooking the castle when the sun comes up behind it. :thumbsup:
It's sooooo much fun to be on teamspeak talking with friends who are also building while building all this stuff.
...especially when you sneak over to someone else's construction site with a 'splody green penis chasing you and try to get him to blow up next to other players mwuahahahahaha :twisted: