If you are in Playa tonight, do not stay in. The city holds El Grito in Plaza 28 de Julio, and it is the one night a year when the whole town turns out for the same thing.
Things start at 9:00 PM. The Grito itself is the centre of it: the shout, the flag, and a plaza full of people yelling ¡Viva México! After that, Ximena Sariñana and Sin Bandera close the night. Sin Bandera playing to a crowd that knows every word is worth showing up for on its own.
It is free, it is outdoors, and it is a family crowd rather than a club crowd, so bring whoever you are with. Get there before 9:00 if you want to be anywhere near the stage, because the plaza fills up fast.
If you have never seen El Grito in person, this is the one to go to.