Stand for holding a Macbook Pro vertically.
Designed to fit the late 2013 13" Retina Macbook Pro model, it will not fit the earlier models, at least not without tweaking the scale. It may work with some of the 0.71" thick 15" models, but I haven't tried it. Also added a larger version that should be more stable (I haven't printed it).
The cutout is asymmetric to match the profile of the laptop, if it doesn't fit, try it the other way around (the bottom of the laptop is more curved than the top).
If you don't have a 3D printer and want one of these, you can get one printed for you at http://www.wallyplastics.com.