Lots of people I've spoken to- including myself- have these wire grid square storage cube cubby system things. (It's especially popular among the college set.) The generic grid square connector (GSC) that comes with these sets is something I've gathered many unhappy sentiments on. This derivative is designed to address many of the problems of the standard GSC.

Download the STL and print it. (You may wish to download the SCAD first and play around with adding some sprues first, depending on the nature of your fabricator.)

Note that I have yet to test this design either for functionality or printability.