Funny ha ha or funny peculiar?
This can be the response to “That’s funny!”
Funny ha ha is humorous and funny peculiar is odd.

I’ve got a funny feeling…
…or a premonition or realisation.

A funny turn is not usually a comedian’s appearance in a variety show, but some kind of sudden debilitating illness, such as a fainting fit or convulsions.

Laugh until you cry.
Laughter and tears can be very close.  Someone with tears streaming down their face may have been laughing.

If you didn’t laugh, you’d have to cry.
This is often said when something has gone wrong.  In my family it was always said that if you accidentally spilt sugar it meant you were going to laugh.  Of course, telling someone this when they had just spilt some always made them laugh!

You’ll be laughing on the other side of your face.
This refers to crying and was a threat made to someone who was laughing at someone else’s expense or perhaps playing a nasty trick.

Rolling on the floor laughing
is something I can remember doing once as a child.  I was reading The Incredible Adventures of Professor Branestawm  by Norman Hunter.  It was illustrated by W. Heath Robinson, who is famous for his drawings of contraptions.  It was the story which made me laugh.

File:Heath Robinson WWI.png

World War I cartoon by Heath Robinson
Wikimedia Commons

Split your sides laughing
perhaps refers to the sides of you mouth.

A barrel of laughs
seems to be the appropriate collective noun.

Christmas crackers traditionally include a joke or motto.  The jokes are terrible!

Grin and bear it!
This is not very good advice.  It makes your jaw ache and so does gritting your teeth.

Laughter is the best medicine.
It really is good for us to laugh.

The name Isaac means he laughs.  Isaac’s elderly mother Sarah laughed when she heard that she was to have a son and again after he was born.  The story can be found in  Genesis Chapters 18 and 21.