I know that IM is already there I just wanted to give an example of a program with good functionality but only cli. The point is that most cli programs are so easy to port they even just run if you unpack the debian package to /opt. Someone could hijack the competition by submitting 10 such applications that can be "ported" in less than an hour, I don't think it's fair. Building a nice UI on the other hand around IM or unison or rsync etc. is a valid entry imo.