I found the Groups feature of the default Android People app not quick enough and a bit bloated. As a sort of exercise, I decided to implement one app that does the kind of job I need: create contact categories, add contacts to them, browse them and call contacts in 2 clicks.

What came out is the skeleton of an open-source app hosted on github (link in comment below).

This is not a commercial product by any mean, nonetheless I would like to meet some kind of "open-source" designer to give it a simple style and a nicer graphics, and then publish in on the Play Store to see if someone else finds it as useful as I do.

Anybody who would like to spend a couple of hours on this is welcome to drop me a line (forks are welcome too!).