Whatever club (ConceptTopic, 5)
From Compile Worlds
The whatever club is the generic name for whatever club happens to be important to a particular manga/anime/game series. See, it's exactly what it says on the tin.
Usually the author will come up for an excuse to make it something specific, such as mahjong, drama, light music, more light music, and even mysterious incident investigation. However, in most cases, it's for no other purpose than to give the series a reason to exist. The first two are clearly exceptions from those cases... and yes, 60% counts as "most".