Here we go:

Lars and his midget/jester companion (Greeble) are traveling through the English countryside for no apparent reason when they come across a chick lass with long flowing locks.  She is obviously insane, having fallen victim to the Stupid Plague — a terrible affliction of the mind which causes adults to dance around like blithering idiots and contort their arms into an ‘S’ position (leading to the name "Stupid Plague").

Almost immediately, Lars and Greeble become infected.  Greeble is infected much worse, because he is a tiny man and has less resistence to the disease.  The three decide to walk through the main road of a dirty village in order to infect as many people as possible.

Soon the Stupid Plague decends on the entire hapless village, prompting everyone to engage in an impromptu Renaissance Festival, complete with maypoles, Punch & Judy puppet shows, burly men banging big sticks together, and dancing chickens.

Lars (played by Eric Roberts) doesn’t seem to be enjoying the festival as much as everybody else, but that’s because he has to constantly brush the hair out of his face.  (This takes place long before the days of barbers and — let’s be honest — hygiene).

The fun ends when a WWII aircraft drops several tons of bombs on the carnival, hoping to prevent the spread of the dreaded plague.