Developer: Craig Smith
Price: free Download on the App Store
Back in the 70's and 80's, when computers where primarily text-based, Interactive Fiction, or "Text Adventures" were all the rage. The first of these, Colosal Cave Adventure (or just Adventure for short) for short, took place in a fantasy cave world. Game interaction is done by typing in words at the prompt. For example, if prompted with "You are in a dark room. There are keys here", you might type "take keys".
Over time, the format for these type of games has standardized into a "Z-machine" format. The Frotz app for the iPhone is a Z-machine interpreter that comes with a number of pre-set games and the ability to load others. We played around with "An Act of Murder" and found it highly entertaining -- and hugely distracting. If you have a lot of time on your hands, this free app is well worth checking out.