The popular “Ballpoint Game” was utilized to tackle the question, whether a superior project approach exists. Two different project approaches have been compared: quick iterations (as know from "agile" management) versus in-depth conceptualization (as known from "waterfall"). The 2-years-experiment involved more than 1,000 participants - and led to a surprising result!
Check out http://overthefence.com.de for more.
Over the Fence - Projects Newly Discovered