tell a joke / crack a joke
Contar un chiste o broma. Informalmente se puede utilizar crack a joke

Before starting my speech, I told a joke to make the audience laugh
My brother’s so funny; he’s always cracking jokes.

Crack up / Burst out laughing
Reírse a carcajadas

My mother always tells jokes that make everyone crack up.
Everyone burst out laughing when I tripped and fell on my face

Hilarious
Muy divertido

The last comedian who performed was hilarious. I couldn’t stop laughing

I don’t get it
No pillar algo. Forma informal de decir I don’t understand.

Everyone else laughed at that line in the movie, but I don’t get it. Why is it so funny?

A joke fell flat
Si una broma «fell flat», significa que no tuvo éxito, no fue graciosa o nadie la escuchó

I told a little joke during my job interview, but unfortunately it fell flat

An offensive joke / a tasteles joke
 broma de mal gusto, o desafortunada por resultar ofensiva

You shouldn’t joke about people with disabilities. It’s offensive
It’s too bad the movie had so many tasteless jokes about women’s intelligence.

the butt of the joke
Si alguien es «the butt of the joke», significa que la broma va sobre él o ella.

My older sister always made me the butt of her jokes and it got really annoying.

Laughinstock
Si alguien es «laughinstock», significa que él o ella está haciéndo el hazmereir o alguna estupidez y el resto de personas se están riendo de él/ella

I was the laughinstock of the company after I accidentally posted an embarrassing picture on the website.

Just kidding
Se emplea para decir que no se está hablando en serio, después de realizar algún tipo de comentario gracioso (o, no) y que la personan que escucha puede mal interpretar.

I’m very short, and my boyfriend used to say that he felt like he was dating a child – but he as just kidding.

Tease someone / Make fun of someone
Se emplea cuando se hacen comentarios sobre alquien, que pueden resultar divertidos para algunos pero no para la persona sobre la que se dicen

I always tease my husband about not knowing how to fold a shirt property
The kids at school teased me a lot because I was fat.

No joke / No laughing matter
Se utiliza para indicar que algo es serio, y no debe tomarse a la ligera.

Getting a virus on your computer is no joke. It can really do a lot of damage.
The guy grabbed a girl’s butt and thought it was funny, but sexual assault is not laughing matter.