What's So Gosh Darned Funny????

So.... I'm editing the job I shot last week at the Ritz Carlton and I come across these images that I just LOVE!!!  When I saw these guys cracking up at the party I knew I had to capture the moment.  I could tell it was really natural and unscripted.  And try as they did, (you know decorum and all), they could not stop laughing.  So I could not stop shooting.  I'm still dying to know what was so funny.....