I co-drafted the new version of the Creative Commons licenses which has been released at long, long last.
I've taken up gymnastics classes after a break of about 20 years. Have managed to get a back walkover without killing myself. (Still working on the back handspring I was terrible at as a child.)
As in Joshua Blaine's original description (below), but may be used to brag about things you've accomplished either this month (December) or the previous one (November), assuming that you haven't brought it up in any earlier Monthly Bragging Thread.