I've posted something similar before but just cannot help myself. Sorry if anyone is annoyed.
There are two parts to Borat which I found the funniest:
A. Borat goes kakaa in the plants of a sidewalk in open view of the outdoor public. A blond lady gives him an angry and disgusted look.
B. Borat gives the southern red-dressed lady a bag of his kakaa. She is still nice enough to show him how to clean up after going kakaa.
Those two parts were painfully hiliarious to me. I was suffocated in laughter. I actually shed tears! My sensation of humor was so intense that my clothes were drenched in sweat and tears after and during those scenes.
I find kakaa to be extremely funny.