I was at a basketball game last night, and my girlfriend began talking about how weird it is for humans to converge all at once, entertain themselves in the form of sports, and then leave afterwards. We then began wondering if any other animals have this form of organized entertainment. We could only think about dogs chasing their tails, but that is not the kind of organized, mass entertainment we were looking for. What’s the verdict?
Dolphins play Maro Polo
I think otters sliding into water comes close.
Whales often gather for “performance art festivals” however they have to keep quiet about it or the Japanese will turn up and slaughter the audience.
For research.
Oh is that the best y’all could come up with?! 
Although I do guess it’s simply possible that we’re the only species that participate in mass, organized, entertainment.
It’s not really quite the same thing, but many aniimals engage lek behavior in which males assemble in particular places and display in competition with other males, and sometimes fight with them, in order to persuade female spectators to mate. The term derives from a Swedish word for games or play.
This kind of competitive display may be at the root of human entertainment behaviors. Considering the commoness of female music and sports groupies, one could easily imagine that there has been selective benefit for males who excel in such performances.
Human behavior differs from those of animals, however, in that both sexes may take part in the displays, and both sexes may enjoy performances by the same sex. Also, at least some humans watch entertainment performances even when they have no immediate interest in mating with the performers. 
Speak for yourself.
This isn’t quite the same thing either but viewers of BBC’s Elephant Diaries will have observed elephants playing football. The game was, however, organised by humans. Also, it’s unclear whether or not the animals fully understood the rules of the game. One baby elephant in particular seemed not to have grasped the specifics of Law 11 (offside).
Besides lek behavior, some social animals engage in coordinated displays among the group members. One example is the wolf chorus (see last section), which may serve to reinforce social cohesion among the pack. However, it may be a stretch to call this organized entertainment.
Another case is the waterfall and rain dances of chimpanzees. From here.
These sorts of displays may come closest to what we call “entertainment.”
I have seen, with my own two eyes, football being played by bears and lions, and I have actually seen baseball being played by orioles and cardinals.
Apparently, horses play football As the link will show.
Sgt Schwartz
I saw a documentary in which a pod of killer whales kept knocking a poor seal off an ice floe. Once the seal was in the water, they would nornally eat it, but in this case they’d just watch until the seal was back on the ice floe, then knock him off again.
It could be ‘whack the seal’ entertainment among whales, but the more likely explanation is that the young were learning how to hunt seals, with plenty of examples from the old ones. This particular seal was very lucky to be in a classroom instead of the cafeteria.
I am not sure that we would necessarily know that the purpose of a gathering was for entertainment. It’s a very interesting question. In Australia we have heaps of parrots. Quite a few of them seem to play in groups, doing all sorts of acrobatic stuff - hanging upside down and waving wings and things. Sometimes it is along telegraph wires, but also in trees. Some of the others are there, not doing acrobatics. They are aware of what the acrobats are doing. Are they being entertained?
I haven’t read much into parrot behaviour, so I am not sure if there are explanations other than entertainment and just having fun. It isn’t, to the best of my knowledge which is acknowledged to be limited, anything to do with mating rituals. The ones I see doing it most are crimson rosellas and galahs. They are certinly entertaining me! Hopefully others know more.
Lynne
actually that probaly was staged. When they make documentaries, they stage a lot of the things.
My cats play Mousie Ball together.