Sometimes you meet someone new and they ask you what you are working on, or you see an old friend or colleague, or a relative, or a colleague outside your field. You have to explain concisely what the quintessence of your project is, in terms your interlocutor will understand. You may have some follow-up questions to answer, depending on the level of sincere curiosity in the question.
I find answering this questions helpful in clarifying what it is I actually am doing--in relation to various audiences. Sometimes I come up with a new perspective on my project by having to come up with a new explanation on the spot.
Simplifying your project for your uncle or your kid's friend's parents can be clarifying. Having to explain it in all its complexity to an intimidating colleague, or in a job interview, represents another challenge. You can draw on these oral explanations when you are explaining your project in grant applications, in prefaces, forewords, prologues, and introductions, conclusions and postscripts, jacket copy for the published book--or anywhere in your project itself where you have to signpost your intentions. You shouldn't underestimate the importance of this skill. It's not for nothing that this is the standard MLA interview question upon which jobs are won and lost: "Tell me about your research."
Later, since I have nothing else to do this week (yeah right), I will be giving some examples or models. I think I am a little better at this than the average academic, so maybe this might be useful.