Casper & Mandrilaftalen, also known as Mandrilaftalen or Mandrillen, is a Danish Dadaist and satirical cult television sketch show that originally aired on DR2 from 1 March to 19 November 1999 across two seasons, comprising a total of 67 episodes. The Mandrilaftalen group consists of Danish comedians Casper Christensen, Lasse Rimmer, Lars Hjortshøj and Frank Hvam. Heavily inspired by British humor, the show became known for its eccentric characters and absurd sketches, leading to multiple TV critics comparing it to Monty Python's Flying Circus. The show is of a talk show format and is hosted by the character Casper, who is a fictionalization of and is played by the program's creator, Christensen. As the star of the show, Casper usually sits at his desk while satirizing the Danish media industry and interviewing fictional guests. Surreal nonsense is a recurrent characteristic of the show, an example being the character Broder Salsa, who folds carpets to resemble great state leaders and sorts capital cities by muesli. In the show, Casper also holds talent shows with fictional participants, presents episodes of fictional TV series and displays advertisements for fictional products. Rimmer, Hjortshøj and Hvam plays an array of various characters, and the show has guest appearances from other Danish comedians, the British Monty Python member John Cleese, the Danish actress Susse Wold, the rapper Al Agami, to name a few. More than 250 different named fictional characters appear in the show, with Broder Salsa, Svenne O'Lotta and Gentleman Finn being the most popular characters according to Christensen.

The show was produced on a tiny budget in a garage on Amager, Copenhagen. Every episode lasts about half an hour and was written, recorded, edited, and broadcast in approximately 14 hours. The manuscript for an episode was written in the morning, followed by the episode being recorded and edited in four hours at most in the afternoon and finally driven to DR by taxi, from where it was broadcast at 11:30 pm. All sketches were recorded chronologically and edited together along the way. The show was a counterreaction to contemporary television programs, which the group considered to be monotonous and poor entertainment. The show had very low viewing figures, which was attributed to its undesirable airing time at 11:30 pm on weekdays as well as DR2's limited national coverage. However, the show received universal acclaim from Danish TV critics and won the prize for Best Entertainment at the Danish TV Prisen in 2000. The show quickly grew a cult following, which led to the launch of multiple fan sites and fan clubs as well as bestselling DVD and VHS releases between 2002 and 2004. In the months after the end of the show, the group toured the country with eight sold-out live shows based on the episodes. They also recorded the spin-off Christmas calendar Casper & Drengene fra Brasilien in less than two days in November 1999. DR2 has since rerun Mandrilaftalen several times, and the show has been referred to as one of the absolute peaks of Danish satire. In 2008, all episodes of the show were digitized and released on DR's archive website, DR Bonanza, where they can be watched free of charge from anywhere around the world.