1066 and All That: a Memorable History of England, comprising all the parts you can remember, including 103 Good Things, 5 Bad Kings and 2 Genuine Dates, is a humorous survey of British history from the Roman conquest through 1930, when the book was originally published. The short book is framed as a mock history textbook, complete with absurd essay questions, pointless footnotes, and a plethora of humorous errors. The authors blend actual history with Shakespeare plays, intentionally mix up people and events, combine quotes, alter timelines, etc., which results in a mixture of clever parody and just plain silliness. If you have a basic familiarity with British history and enjoy the sense of humor of Dave Barry, Monty Python, and/or The Simpsons, you will probably find this book as hilarious as I did.
Thanks for the recommendation, Sarah!