The theme of the Taskmaster House shifts from season to season. It's often quite subtle, but frequently most noticeable through the large portrait of Greg in the living room, which changes to reflect a particular artistic style:
Series 1 has the picture reference Shot Marilyns by Andy Warhol.
Series 2 references Le Sommeil (Sleep) by Salvador Dalí.
Series 3 is based off of Oh, Jeff...I Love You, Too...But... by Roy Lichtenstein.
Series 4 has a picture of Greg painted in the style of one of many of the Vincent van Gogh self-portraits.
Series 5 has the picture parody of The Son of Man by René Magritte.
For Champion of Champions, the main portrait was of Greg as a king, wearing a crown and royal garb. Many things around the house were made gold.
Series 6 has a portrait that references Hand with Reflecting Sphere by M. C. Escher.
Series 7 generally homages Pablo Picasso's "Cubism" style, but specifically riffs on Seated Woman.
Series 8 has a picture that is an original piece made for the show, which references various anime villain tropes; Greg with Tsurime Eyes, an Eyepatch Of Power, holding a cane with a metal hand.
Series 9 has a picture of Greg made up of vegetables, in the style of the painting Vertumnus by Giuseppe Arcimboldo.
Series 10 adopts a western theme, with the picture of Greg being styled as a colourised old-timey photograph of him dressed as Wild Bill Hickok.
Taskmaster's New Year Treat special has a classic cinema theme, with Greg's black-and-white portrait referencing Buster Keaton. The lounge is decorated with a red curtain, with movie theatre props like a popcorn machine, a movie reel, and a projector.
Series 11 is themed around Soviet Russia, as Greg and the Taskmaster house can be seen in a propaganda poster which reads "СОЗДАТЕЛЬ ЗАДАЧИ ЗАДАЧИ НАША ОБЯЗАННОСТЬ", which roughly translates to "CREATOR OF TASKS, TASKS ARE OUR DUTY". Linda the Cow is now wearing an ushanka, as opposed to the Stetson previously worn in Series 10.