Religious slang: Get holy with your Spanish!
Hostia  Lit. Host. Colloquially used to mean several things:
Dar/pegar una hostia  Lit. to give someone/something a host. To hit, slap or smack.
Example: Como no te calles, te voy a dar una hostia  If you don't shut up, I'm going to smack you.
... de la hostia  Lit. ... of the host. This expression is added to nouns to indicate if something's very good, very big or very intense.
Example: Tengo un frío de la hostia  I am absolutely freezing. Se compró una casa de la hostia  She bought a massive house.
Es la hostia  Lit. It's the host. It's amazing, funny, cool or incredible; it can be applied to people and things.
Example: Su nuevo coche es la hostia, tiene de todo  His new car is amazing, it has all kinds of features.
La Virgen María  is Mother Mary, but la virgen, used colloquially, is added to nouns to indicate if something's very good, very big or very intense.
Example: ¡Virgen Santa! ¡Virgen Santísima!  Oh my God! Goodness me! ¡Virgen Santa! ¿Qué te ha pasado?  Oh my God! What happened to you?
Dichoso/a  Lit. full of happiness, usually of a religious nature. However, it's mostly used to curse something that's gone wrong.
Example: Ya se ha vuelto a estropear el dichoso ordenador  The damned PC has broken down again.