One of the most impressive aspects of 3D printing is the capability to create complex mechanical objects with moving parts in a single print. Unlike traditional manufacturing techniques which produce component parts that must be put together, with 3D printing, there is no assembly required! To illustrate this feature, we have recently begun to use our 3D printers to produce adjustable wrenches that actually adjust! The process is simple: We just download the design file from Thingiverse (Thing 139268 by barspin), put it on an SD card, insert the card into one of our MakerBot Replicators, and hit print.  We then sit back and watch, and 40 minutes later, we have a fully functional adjustable wrench. To see our wrench in action, stop on by our lab. Or if you have a 3D printer, a laptop, and an internet connection, you can print your own.  Welcome to the future!