Going out: Learn the true meaning of "marcha"
Ir/Salir de marcha  Lit. To go out on parade. To go out and party and have a good time. Other words you can use in its place include juerga, movida, farra .
Example: ¡Menuda marcha hay en Ibiza!  What a night life there is in Ibiza! El fin de semana me voy de juerga a Madrid  This weekend I'm going out partying in Madrid.
Pasarlo bomba/en grande  To have a great time.
Example: Lo pasaron en grande con Anita  They had a ball with Anita.
Un chiringo/chiringuito Although it literally means a beach stall selling drinks and tapas, it also refers to most drinking bars/pubs. Ir de chiringos is a common expression that means to go out drinking.
Un garito  Una garita is a sentry box, but this slang masculine version refers to any drinking venue.
Example: Esta es la zona de garitos  This is the area where the bars are.
El/La de la vergüenza  This is the name given to the last bit of food left in a shared plate of food. Literally, it means "the one that brings shame" because everybody feels a bit guilty about taking it.
Example: ¿Alguien quiere la de la vergüenza?  Anyone want the last one? No, cómetela tú. No, you can have it.
La Dolorosa  is Our Lady of Sorrows. It literally means "the painful one" and is used to refer to the restaurant bill in a sarcastic way.
Example: Pide la dolorosa, veremos cuánto nos clavan  Ask for the bill, let's see how much they rip us off for.