I have a bunch of block ideas but not much time- if you have some time, feel free to use these+submit to mp
Simple
random page- link to random page, admin can select page that random pages will be child of
classifieds- modify forum block
Request friends- extend social network for the ability to accept/deny friend request, not accept automatically
Advanced
backend ftp
better uploaded file urls (not yoursite.com/files/323/4323/untitled.jpg but yoursite.com/files/images/untitled.jpg)