Gave my first ever public talk. It was an hour long, to a it thirty teenagers, at Liverpool University (I'm 16, btw).
I started from randomly selecting cards in a deck and got all the way to proving Bayes' Theorem and talking about its implications.
Whilst wearing my Bayesian Conspiracy t-shirt.
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.