Laugh Life
The time period during which something is generally accepted as funny. After a given amount of time, known as the laugh life of the joke, the joke has run it's course and is no longer funny.
Chuck Norris jokes are a great example of jokes that are past their laugh life
Im laughing my life away
Laughing so f***ing hard that you feel lifeless after this episode.
"Oh god. Jessica told me what her boyfriend did last night and Im laughing my life away.
laugh life off
Don't be too serious and just laugh the thing/things away
We try to laugh life off. Laugh's fun, but often behind our laugh is a hollow ring. --The Meaning of Life by Norman Grubb