The Spellman Files (2007) is hilarious.  

First book in a comedic mystery series by Lisa Lutz that follows the chaotic lives of a family of private investigators in San Francisco.

The story is narrated by Isabel “Izzy” Spellman, a 28-year-old PI with a checkered past who works for her parents’ firm, Spellman Investigations. In a family where snooping, tailing, and wiretapping one another is the norm.

If you are looking for an easy read with a lot of laughs, check it out.