Parsely games are inspired by Ye Olde Text Parsers from days of yore, but substituting a live human for the computer parser.
From the RPG site:
[…] The Parsely engine, created by Jared A. Sorensen, is really quite simple: it's a way of playing an 80's style text adventure game without a computer, or rather, with a human pretending to be a computer. Instead of typing "GO NORTH" or whatever, you simply speak your commands, and the "computer" tells you what happens. A Parsely session is a lot like every other RPG (Role Playing Game) system except that the Dungeon Master is an android who only understands a limited number of commands and instructions.
Parsely is a cross between two great game systems that work together, like hot fudge sauce and vanilla ice cream, to create something that's even better than either component alone. (Most writers probably would have gone with the peanut butter & chocolate analogy, but that one seems overused to me.)
Parsely games are better than old-school text adventures in lots of ways. Firstly, it changes a solitary activity into a group event, transforming something that isolates people into something that brings them together. Secondly, it's just a lot more fun telling your commands to a friend rather than typing them into a computer. (Yes, even when that friend is deliberately slowing you down with "syntax errors.") Thirdly, human-ware is more sensitive to the player's needs than hardware, and thus can react to player frustration with hints. Lastly, and perhaps most significantly, it's vastly easier to create a Parsely scenario than to program a full-scale text adventure game. […]