There's not a lot of structure to vanilla Minecraft's multiplayer. You build, you admire, you take a giant isometric screenshot and admire some more, then you discover creative mode and TNT. Then you restart the server and promise to never do that again (unless you're 2b2t, then you just keep on going). Then someone mentions mods, and you get lost looking for something to give the game scope. There's nothing wrong with vanilla, but if you're looking for a server that turns the world into a more interesting place to explore, and eventually claim bits of your own, take a look at the CivCraft server.
It's a bit Honey I Shrunk The Kids, sticking you down on the ground of a vast game of blocky Civilization: you and some friends will join together to build a town. It's hugely involved, with you mining the ground to gain resources to trade for coins to claim your land. Like a proper game of Civ, major construction involves clicking on the ground and watching the buildings extruding upwards. They're functional buildings, allowing you to enter and use them, and enhancing them to provide the bonuses to the land.
With your town hall in place, you can then start to create your town as you'd like, including Cultural and Defensive buildings. The more you grow, the more influence you'll have. Grow crops, advance along the tech trees, build more towns. All the while a vast game of diplomacy is taking place server-wide. You can take part in the more Civ-like metagame, except it's not meta: you're actually on the ground. Spies, for example, can sneak into enemy towns and destroy their Wonders.
It's currently offline, because of a huge surge in popularity over the weekend, but it'll be back up in a few days. I don't have the time to oversee an RPS invasion when it comes back online, but you guys should totally be in there, building an empire on puns.