The lightweight and modern Linux desktop. LXQt is what I used to work on (I still help out once in a while), and it just doesn't have the manpower and organization required to produce something really good.

Working on the Desktop is a really interesting thing. The goal is to turn machines into something usable for, nowdays essentially browsing the web or gaming (with the oddball app that does more than that).

It's a very rewarding thing. Hit me up if you are interested: Swing by the #lxqt channel on IRC and DM me (jleclanche, or agaida if I'm not here). It's a place where you can get to either work on stuff that already exists, or make up your own new ideas, or help bring standards together.