Lately I have been spending most of my time using and upgrading my makerbot thing-o-matic 3d printer. I have been using it to print parts for school projects such as robot chassis (not online yet) and a stereoscopic camera mount (http://www.thingiverse.com/thing:8050).
I have also been designing and printing things because I wanted to see if I could. Most of those can be seen here: http://www.thingiverse.com/J_Hodgie/things.
I have also been printing some upgrades for the printer because I want the quality as high as possible so it can print parts as small and reliably as possible. The upgrades I have installed are printing some gears and changing the dc motor to a stepper motor. I also designed a tool holder for my commonly used tools and upgraded the automated build platform belt from plastic to titanium.
As I am writing this my extruder is also in a few pieces as I am upgrading to a dual extruder setup so I print with PVA supports and soft PLA as integrated hinges.
Overall, DIY 3D printers allow me to cheaply create whatever part I need, so it is very handy to have around if you can maintain one.