I've had Blockland for a few years now, I still play and build regularly.
Blockland is an ever-changing, ever-growing community, I don't understand how anyone can get bored of it.
There's always something to do, countless possiblities. There's something for everyone, if you can't build, blow each other up in a DM, or play a challenge server.
But what I enjoy more than anything else is building with friends, that way, the fun is ceaseless.