Can there be a simple description of "Simple Church?" You'd think so! Roy McClung at Maximize My Ministry took a shot at it in the video below.
Note how he takes pains to be gentle in the comparison of simple and institutional church forms, stating that he is "in no way attacking" the more familiar form. I have found that spirit to be common among the people I've encountered who are pursuing simple church (e.g. House2House and CMA). It's a very good sign.
If you like napkin diagrams you may want to look at the one I've posted that shows how most of our resources are spent on the least effective things in conventional church settings - again, an argument in favor of simple church. I'd also like to point out that I used a real napkin, which is more simple than Roy's fancy-schmancy video. So there.