THE MERRY WIVES OF WINDSOR -- At the Folger through January 21.

"The Merry Wives of Windsor" is a spinoff. Queen Elizabeth I is said to have thought the character of Sir John Falstaff so good in Henry IV, Parts I and II, that he deserved to have his own show. As today, when such suggestions come from on high, they are usually followed, even if the author is eager to get on to something more challenging and serious.

If the production QE-I saw was as funny as the Folger Theatre Group's, it's a wonder she didn't try to keep Shakespeare turning out endless farces around the other likely characters -- the Ford family, Mistress Quickly, Doctor Casius would all lend themselves to endless plot possibilities -- instead of trying his hand at such riskier types as Julius Caesar, Othello, King Lear and Macbeth.

"Merry Wives," after all, covers his themes of jealousy, greed and love without parental consent, and if it doesn't deal with them in depth, well, it took only two weeks to write. And while it may not have many lines you can take home and quote for the next 400 and some years, it's a comedy that works.

But neither the sponsor nor the writer gets all the credit for that. Read today, "Merry Wives," with its footnoted puns, would not have you split your ruff laughing. At the Folger, with the most spirited, imaginative and silliest of productions, directed by Mikel Lambert, it does.

One could call it rollicking and bawdy, or translate those terms, which seem to be used only in connection with the classics, and admit that it's hilarious and dirty. There isn't a chance for a pratfall or leer that's overlooked, and comic business, as crude but funny as sitting on sharp objects or ripping trousers, is constant.

William Penn's music is cartoonized Elizabethan, with what sounds like duck-honking and moose-calling right in there with the plucked strings. Hugh Lester's sets of bright greenery clank open and shut, and one time when a character gets left outside, he has to knock on the trees to have them open.

And each actor is going full strength with whatever Shakespeare has provided in the way of intrigue, stupidity or funny accents. The merry wives -- Mistresses Ford and Page, objects of "the greasy knight" Falstaff's bloated lust -- are, as played by Glynis Bell and Helen Carey, so full of lusty merriment that it's irrestibly catching even when they're only bystanders to the action.

Peter Vogt, as Ford, seems to perform literally the part of a man beside himself with jealousy -- his limbs, his neck and even his tongue keep shooting out involuntarily. At one moment, while disguised in a marvelous costume by Jess Goldstein, he acts through a barrage of pink and orange feathers. Albert Corbin and Ralph Cosham take the parts of the comic Frenchman and the comic Welshman respectively (although the Welshman has something of a Peter Sellers Indian about him) and add all the funny foreigner touches to the dialect Shakespeare provided. Marion Lines is crackling with visual wisecracks as Mistress Quickly, and Leonardo Cimino is a wildly dotty Robert Shallow. There's hardly a walk-on part that doesn't bring its own laugh with it.

And what of Falstaff? Thomas Carson has such roaring presence in the part that it's a shame not to see him in the great Falstaff roles of the history plays. As funny as the spin-off is, it suffers, as do many such quests for more of a good thing, from watering down.