A simple game with a GuessingGame class and a script play_guessing_game.rb that coordinates the whole thing.
It takes a maximum and a minimum and finds a random number in the range (inclusive of max and min). Your job is to guess. Once you get it right, it tells you how many tries it took. Oh, and there are tests too!
The Gemfile.lock has all the gems and versions. Clone, bundle, and have fun with ruby path/to/lib/play_guessing_game.rb!