Do the tango! Actually it’s the Tango Desktop Project. Its objective is to give users a consisent look and feel with the open source apps they use.
I find this project interesting because it involves user interface. Time and again I have wondered about user interfaces and icons. I have played around with various desktop environments and have seen all sorts of icons. Some people are turned off with open source software because the user interface doesn’t look as good as what they have been accustomed to. However, I think that times have changed and icons actually looks pretty polished. This project takes it one step further by attempting to give the consistent look and feel by making the icons work across various desktop environments. The project also involves a standard icon naming specification.
Some of the people involved in the Tango Project are those who have worked on GNOME project. And at the bottom of the people page is an invitation for everyone to participate in this endeavor. There are guidelines in the wiki so you could check them out if you want to be a part of it.
I personally would like to see how things turn out and how consistent things would look like.