I’m old enough to remember when Lego was little more than rectangular bricks of various dimensions and colors, so you had to use your imagination to build stuff – after walking uphill both ways, of course. This means I’m snooty about prebuilt sets.
Having said that, this is awesome: A Lego version of the Mount Washington Cog Railway. It’s on the Lego Ideas site, a super-blog for DIY kit designers.