Wow, that's a tricky one already. I thought the new guys were going to go easy on us!
Recently, however, I've actually played games! And played, rather than GM'd, which is also a miracle. As for "Best Game Session since August 2015"?
It could be moment when the doppelgänger we were chasing in our Victorian era Changeling game suddenly shattered into glass which left all of us stunned with our jaws hanging open.
Or flying a recently stolen Lambda class shuttle into the luxurious abode of the former Jedi classmate who had gone bad in our FFG Star Wars game?
No, I think the best game session involved the moment in our Clone Wars era FFG Star Wars game, where our party of apprentice Jedi were sent on a mission to find another group of apprentices who had gone missing. We'd found them, battled the bad guys, and lost a few of the clone troops that we had with us along the way...
We were just heading back to the ships, with the remaining sixteen or so clone troopers, victorious but badly beaten up, when the clone commander ahead of us at the ship receives a holographic message.
"Execute Order 66"...
And suddenly, our Clone Wars game becomes a Rebellion Era game...
Until next one, stay multiclassy.