I was at Gophercon 2015 in Denver a few weeks ago and tried my hand at a programming challenge hosted by CoreOS. Unfortunately I didn't end up finishing it and was sad that they no longer had it up after the conference. I did what any rational person would do and tried recreating their challenge.
You play the game by opening up a raw tcp connection and joining a channel with a few friends. The point of the game is to send a third party sensitive files without getting caught by security. Behind the core of game is a fairly complex and practical math problem, the multiple knapsack problem. I wasn't able to implement an algorithm for solving the MKP yet so that I could generate random problems and calculate a top score, but that is in the pipeline of things to do. For now, I have taken a sample problem from a textbook that is quite easy to solve and no top score is listed. I also want to create a seed of names from which to generate problem data. Of course, you could in theory solve this challenge without any programming at all, but that wouldn't be much fun now, right?