For long time now, we've been using the Scrub Daddy line of sponges in our kitchen. They've typically either been set on the edge of the sink or (on occasion) stuck on the handle of the faucet using the ‘mouth’ of the sponge. I searched to see if someone had made a holder for them already, but the only one that I found just didn't fit my needs (mainly because it hung down into the sink and made getting to the sponge difficult if there were dishes in the sink). 

So, I measured our faucet and sat down with OpenSCAD and threw together a quick and simple holder that would print without supports and, in general, should print in under an hour with most printers. It's very rudimentary- it's like less than 10 lines in OpenSCAD- but it does work well enough. 

You'll need to print out two of the ‘hooks’ and one of the links- just place the hooks over your kitchen faucet and slide on the link, and the sponge will rest with the arms of the hooks through the eyes of the sponge.

I've uploaded the OpenSCAD files for the parts as well, since faucets will differ and the hooks may not work well for everyone. I printed the parts with a .2mm layer height, but pretty much anything will work.