Reality Lag is a creative bunch, we always have ideas that needs testing.
To spend time trying out new ideas in the most productive way, we have set some simple limitations for making game prototypes. Each game prototype is a 100 working hours project. When the 100 hours are spent, the prototype is done. As we do not sit full time on this, the 100 hours are usually spread over a couple of weeks, giving the project lots of brain time in between the hours we are sitting with the tools in hand.
Before we even go there, we like to have the idea fleshed out to be certain what is in and out of scope. So, we make use of what we call a PowerDoc. The rules are that the idea must fit with in one page (doodles excluded). The PowerDoc must contain a short description of the Concept, a target audience or platform, a simple description of the core mechanics, and a more specific description of some win/lose conditions.