I mean "hardest laugh of an entire year" laughs. Almost falling out of my chair laughs.
I can remember times that came close to being the hardest I laughed in an entire year, but not quite: like in August 2005, at Cinema 21 in NW Portland, alternating between roaring with laughter and yelling "Oh my God" at the documentary The Aristocrats, where comedians discussed what's supposed to be the most offensive joke in the world. Almost the hardest I'd laughed, but not quite. What was my hardest laugh in 2005? I no longer remember.
But in 2006, it was when I watched the Invader Zim episode "Battle of the Planets" for the first time. (The soda can!) This was during a time when my work stress went up significantly, because my new-ish manager at the hospital at the time was possibly the worst manager I've ever had. I needed that laugh.
In 2007, it was watching the surreally funny stoner comedy Harold and Kumar Go to White Castle. There's a dream sequence involving, um, er, a bag of pot. It's dense with visual jokes, even by the standards of that film. And I, again, almost fell out of my chair.
In 2014, it was when I was at the Bagdad Theater in SE Portland, watching the first Lego Movie.
...I have laughed since then. Plenty. But these laughs: they've stayed with me.
Think of stuff that's made you laugh very, very hard. You might feel better.