I play Minecraft regularly myself~. It's a good way to pass the time when I need to and it's rather fun while doing it~.
Ah, the most impressive thing I've built though? I don't really have anything majorly impressive myself. But I was rather proud of going about my one world, scrapping up a bunch of clay, and building a two story giant brick house.
I'm not an amazing builder, so the things I've made are probably rather small compared to some others~.