Cologne, Germany. I'm running a 3d printing workshop on the weekend here. If you're interested, have a look at http://dingfabrik.de/2011/11/24/3d-drucker-an-einem-wochenen... (same info in English at http://blog.reprap.org/2011/11/reprap-prusa-iteration-2-buil... ). There's only a couple spots left though.