Frankfurt, Germany convention March 2009. I did this biomech-inspired hourglass on an awesome dude named Markus who has an impressive collection of work on his body. I was flattered to get my chance to add on to it.
Update April 2010: Got a chance to expand this piece down onto the knee during the first annual Tattoo Ink Explosion Germany. You can see the expansion photo under the 'detail image' link.