Yoshimoto Kougyou is a very famous production company that manages many of Japan's popular comedians. And yes, most of the comedians are from the Kansai area with the most popular and famous being Downtown, London Boots 1-go 2-go, Tommy's, Yamada Hanako and Fujii Takashi. But what many people don't know is that they're not just limited to comedians. They also manage other talents, such as Komuro Tetsuya and FayRay and even Hasegawa Shigetoshi from the Seattle Mariners!
But they are primarily known for their comedians, due to famous duos like Downtown, Tommy's and London Boots, who have perfected the "manzai" form of comedy, which started off being very popular in the Kansai area and has now spread through all of Japan. "Manzai" is usually performed by two people (sometimes three, but most comedy teams in Japan now are a standard two). One "boke" who says or does stupid things (ie., usually Matsumoto Hitoshi) and one "tsukkomi," who is the "straight man" (ie., usually Hamada Masatoshi)--sort of--who points out their stupidity and usually slaps their partner on the head.
I personally love Downtown, hence my using them as my examples.
I watch them every week on HEY!x3 and they always keep me laughing! Macchan is the perfect boke--he even looks the part!