Many modern shampoo bottles have a flat top that allows you to set it down top-side-down. Unfortunately, the brand of all-natural crunchy-granola urban-hippy shampoo that I use does not have such a top. I either cannot get to the last little bit of shampoo or I have to do something creative with the bottle: balance it, wedge it against something, or do a quick centrifuge-style flick of the bottle. None of these work all that well in the dim, pre-coffee hours of the morning.
I thought to myself: self, you have some decent 3D modeling skills and you have a 3D printer, so you might be able to improve this annoying part of your morning.
So I designed a shower caddy to hold my shampoo and conditioner upside-down. The main features are cylindrical holes to hold each bottle and a wide, flat base to help keep everything upright. At the bottom of each bottle-gripping cylinder is a draining hole that links up with a draining trough running to the front of the caddy.
The whole thing works pretty well and the source file can easily be reconfigured to your brand (and more specifically, geometry) of shampoo. The 3D model, source file, and everything else can be found on the Shampoo Caddy Thingiverse page.