In case you haven't heard of Minecraft, it is a bizarrely addictive open-world game where you hide from monsters all night and spend all day remaking the world to suit your whim. I chopped down trees, mined minerals, and ended up with both a fairly sweet keep built into a cliffside & a house floating on a glass platform high above the sea. It is all fun, but was starting to get a bit boring.
Then last night as I was trying to fall asleep I was possessed of the urge to build a 100block x 100block x50block high pyramid of glass/ Why? because I can. I'm currently torn on making the inside a sort of bio-dome vs something even more insane (stone inverted pyramid shape hole underneath with a "house" suspended in the center is the current thought).
Of course to build a pyramid of this scale I'd be looking at shoveling up every beach in the world for enough sand to smelt into the 10,000+ glass blocks I need, then either leveling massive forests or strip-mining the planet to get the charcoal or coal I'd need for the smelting.
Minecraft. Not only do we destroy your free time, but we encourage you to destroy the planet. :)