eXtreme Programming (XP) in OSS projects?

ivi asks: "I first bumped into the XP approach to system development, some years ago, on Dr Dobbs' now-defunct Seminar-On-Demand site TechNetCast. XP has some short, simple rules for growing software from Users' Stories, eg, with programmers working in pairs, showing prototypes to Users "early & often" et al. Download this XP site (under 400KB, zipped) for more. So, who's used or using XP, does it work for OSS projects & what have your experiences been with it, so far?"