I attended the "Panda Palooza" farewell event today. In case you are curious what it was like, it's always a treat to see the pandas and other animals, but it mostly just felt like a normal visit to the zoo (albeit really crowded and with a few extra photo ops).
The specialty panda cookies and coffee drink were sold out (there were a few panda themed ice cream treats available, but those were the only food specials), the scavenger hunt sheets ran out before my group got one, I did witness some live music but it was so loud I couldn't even get close enough to see the performers, and there was apparently a dance party near the bottom of the hill that ended before we made it down there, but other than that, it sounds like the only other special panda-themed thing was screenings of a documentary in the visitor center. The zoo was so crowded that the line to see the pandas reached down past the elephant house and the line to get into the ape house stretched down to the reptile house.
I'm still really glad I went-- despite the crowds and warm weather, the animals were really active and I got to see most of them, including all 4 Andean bears being really playful-- but in case you were wondering what the panda-themed party was like, I don't think you missed a huge amount!