Slapstick all the way
Japanese comedy is very heavily dependent on slapstick humor. One perfect example of this is the special new year's program shown every year in a unique episode.
It's called "gaki tsukai ara-hen de", and it basically plays on the Japanese typical game called "batsu-game" (batsu is just the vocalization of X...), which is a challenge game involving punishment for losing. In this case, a slap on the behind with a foam bat.
This new year's special is based on the principle that the participants cannot laugh no matter what happens. The participants are taken on a planned course with funny obstacles on the way. The premise of the show makes it very difficult not to laugh for both viewers and participants alike. Although there is some funny subject matter, the fact that the participants are being spanked is the funny part.