As part of our XWiki Days we had our first Improvement Fixing Day on the 6th of March 2014. Its goal was to close the maximum of JIRA issues of type "Improvement" by taking low-hanging fruit and taking the occasion to clean up our improvement list (duplicates, won't fix, etc).
We had 4 participants and we managed to close 18 improvements (8 real fixes).
FTR here's the graph of all non bugs.
Thanks to all the participants!