I'm a big fan of Jasper Fforde's series about Thursday Next, Literary Detective, and have had the two installments (thus far) in his "Nursery Crimes" series waiting on one of my TBR shelves for awhile. They're fairly quick, clever, and amusing reads, full of outlandish situations and characters, plus some groaningly bad jokes.
I really never read many nursery rhymes or fairy tales to my son when he was young - you may have noticed the dark undercurrent many of them have. If you haven't, Fforde will be happy to help point it out to you:
"The Nursery Crimes Division (NCD) of the Reading Police Department is chronically beleaguered, under-supported, and disrespected. Under the direction of Detective Chief Inspector Jack Spratt, assisted by Sergeant Mary Mary and Constable Ashley, they are responsible for investigations involving PDRs (Persons of Dubious Reality), and they often find far more to incidents than meets the eye."
The first book in the series, The Big Over Easy, opens with the shattering death of an oversized, drunken egg. Did Humpty Dumpty fall off the wall - or was he pushed? Or was there some other cause for his demise? Jack and Mary's investigation digs into Humpty's complicated finances and personal life - he was quite a womanizer, for one thing - and uncovers a conspiracy involving genetic engineering and a plot to spread foot disease. There's also a side plot involving Jack's mother and a giant beanstalk.
The events of The Fourth Bear unfold several months later. The NCD's improved reputation after solving the Humpty Dumpty case has just taken a beating from a snafu involving a wolf and a girl in a red riding hood, and Jack has been placed on suspension. Not that it stops him from being involved in investigating the disappearance of reporter Henrietta "Goldilocks" Hatchett, last seen leaving the home of the Bruin family. This case ends up involving national security, more genetic engineering, and the rights of bears in society.
Sometimes I just want to read something silly, and these books are silly in the best way. Don't look for much in the way of theme or character development; this is plot-driven satire, built on an unexpected yet familiar framework, and it works just fine on that level. Overall, I didn't find these books quite as "smart" or developed as the Thursday Next books, but since the source material is downscaled a bit - nursery rhymes vs. classic literary works by Austen, Dickens, and Shakespeare - that seems fitting. If you enjoy silliness, and I do when it's a well-done as it is here, they're good choices for a fast diversion.