Too damn cool not to link. OK, current RPPR members, get your Legos together and play Quiet Year again: http://www.theatlanticcities.com/design/2013/02/imagine-playing-sim-city-real-life/4652/
I simply love the idea of using Lego* as a 3D game map.
*= In the UK Lego is used to refer to the singular and the plural. Otherwise we'd have Legos land.
We Americans like to put "esses" (which we'd spell "s's") on everything.
Also, for those that don't have a lot of money to buy Lego(s). There is the Lego Digital Designer that you can buy for free:
http://ldd.lego.com/en-us/download/Imagine it like Minecraft without griefers.