Yeah, that was the 4th of July CERN seminar where first CMS (my experiment) and then ATLAS presented their preliminary results showing that the search for a Higgs like particle gave statistically significant results allowing us to claim that we thought the particle had finally been observed. The run up to that meeting was a few weeks in coming, ca 7 days before we didn't yet know if we had enough statistics or if the particle was still there in the latest data (we had looked through about half the year before). Then in some internal "locked" meetings the data was first presented to the collaboration and everyone was sure that we'd finally found the elusive particle. Higgs and Englert were strongly advised to come to the seminar which gave people the hint that this might be for real
It was nice to be first (the December 2011 seminar was ATLAS first, CMS after so the order was reversed for the 4th of July one) because in effect when CMS showed that we'd reached 5 sigma significance (the de facto standard in particle physics for discovery) the auditorium went nuts. Noone really cared about ATLAS talk beyond the fact that they too saw the particle to the same significance.
Fun fact: The 4th of July seminar was the first time Englert and Higgs met. In the prior 50 years since their publications they had never met at any conference or what not event.
I personally wasn't at CERN that day, but was giving a parallel press conference in Estonia with all possible media invited, it was a memorable day