This is one of the most contagious and lovely baby laughters in the database, in my opinion. The baby cannot be many months old and just laugh her heart out!
Sometimes you get the impression that bringing out the camera itself is a reason for people to laugh, like here.
This baby is laughing like crazy at…er…dad folding the laundry!? 
This is a collection of cats with voice over-laughter. I especially love the crazy cat laughing at around 0:50!
A really happy toddler laughing and playing.
This video clip is quite interesting in how the couple interact with each other while laughing. Note the body language of the two. This truly highlights the fact that laughter is a form of communication.
I personally love this one. It is one of those contagious laughter for some reason mostly teenaged girls often get caught in, when you just laugh and laugh and…