Best game session since August 2015?
I had to check, because "Negative Crisis" was in June 2015 (has it been over a year)? That multi-genre, multi-campaign session was a lot of fun. But, it's outside the envelope so I'll go with the closing session of my massive D&D campaign. It featured the entire gaming group and a second GM helping me run parallel sessions. The ending was a little bit of a letdown, but it was nice to end a campaign on a neat and tidy note.