I wanted to build a project with the ESP8266. I've purchased a few in various form factors. They were a little annoying to program because of the extra circuitry, etc. I found the NodeMCU, which is basically a dev board for this chip, with built-in USB and accessible GPIO headers.
I also happened to purchase a really cool LEGO train, so why not combine the two?! 
I bring you a WiFI controlled LEGO train!
http://www.internetoflego.com/lego-train-automation-wifi-controlled-nodemcu-esp8266/
