Today there was a game for programmers online - Operation Go . In my opinion, this is a very high quality game made in which you need to go through missions, understanding, disassembling and adding code to Go. All this with a plot, development and plot, a good soundtrack, interesting and addictive. You act as a secret service agent who regularly has to deal with problem solving with code.
Very cool done, really. Try and get ready to discover some new aspects of Go or the standard library. Some levels need a mathematical concept. Well, English, of course.
I would put such toys at interviews to candidates and watch how a person decides. ')