I can't possibly understand why anyone would find anything related to the Geico Cavemen funny.
The characters are near
blatant rip offs of Phil Hartman's character in his 'Unfrozen Caveman Lawyer' SNL skit. Basically the same concept; middle-aged cavemen living and working in an upper class society, with cocky, modernistic attitudes.
The difference is the SNL skit was somewhat original and entertaining, while these clowns are pathetic.
Unfrozen Caveman Lawyer