And sub categories as Stories, poems, essays, paintings etc...
It is more or less a crime to call art as sub category of entertainment. The purpose of art is not entertainment. Entertainment is one of the many goals it can achieve.
Including humour as subcategory in offbeat and personal is only humorous. Because what do we do when we need to seriously laugh about the everyday official affairs? We can't call it offbeat and personal. Can we? We can't put humour under anything. Because eveything comes under humour.
These are my humble suggestions. I hope you agree.