Do you know "2048" -- simple, addictive game ever ?
I've got a 4096 tile after 6 hours of play, which is probably difficult as hack the app to cheat it or make a heuristic algorithm to get it! Recent research shows even if you are the most unlucky, you can make a 4096 tile or more.
Challenge me? A web version is available at http://2048game.com/
Bye!