Here are the boundaries for words about games.

VIRTUAL ENVIRONMENT

• Needs autonomy, presence, and interaction
• Encapsulated such as a tele-meeting or fake rainforest
• Abstract environment (NOT physical)
• Textual or graphical
• Nonphysical interactive spaces
• Imaginary skits/games

GAME

• Merriam Webster– “Activity for fun”
• Lambda MOO = “not a game”
• Rule governed, goal driven
• MOO = Game or chat?
• Poker and Russian Roulette are fun for some, but are they games?
• Everyone acknowledges it as a game
• Games might not be fun for all because it is based on an individual's entertainment
• Game may not be fun, or is just bad overall

To be FUN, a game needs

• Rules
• Intrinsic motivation, which may be highly individual
• A purpose
• To be engaging
• To have presence

RULES

• Show success / failure (zero-sum result) in the environment
• Make up as you go, make your own goals. (Sims)
• Explicit? - sometimes not 
• Everyone knows the rules.

PURPOSE

• Acknowledges designer's intent to make it a game.

INTERACTIVE

• Manipulation, what can you change?

ONLINE/OFFLINE

• How a game is distributed
• Suggests the hardware and other requirements for the game
• Video/Console, Computer, Online games may cross online/offline boundaries -- e.g., for multiplayer/single player modes, or other modes of play.

Acronyms

• MOO = MUD Object Oriented
• MUD = Multi User Dungeon
• MUSH = Multi User Shared Hallucination (?)(http://www.idyllmtn.com/mush/what.html)
• MUSH/MUCK = word play on MUD

• A digital game is an interactive program for one or more players, meant to provide entertainment at the least, and quite possibly more.
• An adaptation of 'traditional' game systems, with rules, player representation, and environment managed through electronic means.
• Any game that involves electronics in some way.
• A digital game is any game played on a digital device.
• digital game: any type of electronic environment that can be controlled or manipulated  by a human user for entertainment purposes
• A digital game is a set of rules and goal(s) abstracted by a digital medium.
• A digital game is a compelling user controlled experience on a microprocessor controlled device.
• A digital game is played on a electronic device and is rule-governed and goal-driven.
• A digital game is a piece of software, embedded or otherwise, meant to entertain its users by presenting some challenge to overcome.
• Digital game - a game that can be played and is interactive on electronic devices such as consoles and computers.
• Digital games is a bad term, because digital really means "of or relating to digits" which includes number, fingers, toes, etc. Digital games are any sort of interface designed to be fun that is controlled by a computer processor. A digital game doesn't necessarily have to be interactive, but it helps.
• A digital game is any game (where a game is something fun) played on a digital device such as a computer or a cellphone.
• A digital game is a system that enables a human and a computer to interact according to set of both implicit and explicit rules, in an electronically powered domain for the purpose of recreation or instruction.
• A digital game is a game played using digital technology.
• A digital game is an electronic stimulation for educational or entertainment purposes.
• A digital game is any form of electronically mediated game.  A game is a form of entertainment with competitive or role-playing elements. An activity that is not interactive and doesn't have a goal cannot be defined as a game.
• A digital game is any game that is mediated by an electronic form -  a PC, a console, a cell phone, etc.
• An interactive electronic media with a set goal(s) or intent(s) for  users to attempt to accomplish.