Well, both the holidays and the Off Broadway theatre have a real down-to-earth reason for celebration. "Nunsense," subtitled a "new musical comedy,": which recently opened at the Cherry Lane Theatre, is the wittiest, most fun-filled evening of musical comedy to hit this berg since George Hearn sang "I Am What I Am." The upbeat score, by composer/lyricist Dan Goggin, pulses with both merriment and a fine sense -- of the subtly dramatic. And while "Nunsense" is rather broadly irreverent, especially to those who may have been reared in the strict confines of a traditional Catholic education, the spirit of the evening touches us with its unabashed desire to delight and make us laugh.

The improbable premise of "Nunsense" is in itself enough to make nearly anyone squeal with laughter. The members of The Order of the Little Sisters of Hoboken are in dire financial straits. It seems that their rather addlepated cook, Sister Julia, Child of God, served most of the holy community some contaminated bouillon. Now, Mother Superior Mary Cardelia (Marilyn Farina) decided to bury all her dearly departed, except for four. These she's stored in the convent's large ice box, creating a festering group of "blue nuns." What has she done with the remaining funds? Why, what any "with it" mother superior would do -- purchase a betamax. The convent, now threatened by the Hoboken Board of Health, must find the funds to bury their sister stiffs. They decide, in the best Mickey and Judy tradition, to put on a show. And that show is the remainder of the evening.

The five-member cast performs with a cornucopia of comic flair and brio: Marilyn Farina's broadly drawn, boisterous mother superior sets both the tempo and humor for the entire evening. She's ably supported by Vicki Belmonte's occasionally bitchy Sister Hubert who manages to bring down the house in a gospel parody called "Holier Than Thou." Semina De Laurentis steals the show as the amnesiac Sr. Mary Amnesia and really makes the rafters of the Cherry Lane ring with her vaudeville-like "I Could've Gone To Nashville." Christine Anderson's Sr. Robert Anne touches with "Growing -- Up Catholic," a paean to the old faith before modernization, while Suzi Winson, as novice and ballet dancer Sr. Mary Leo, puts the final touch on the ensemble with her quiet sense of comedy.

Kudos to Felton Smith's high-hoofing choreography and to Dan Goggins' spirited direction. Barry Axtell's set, a combination convent and "Grease" set, underlines the comic texture of the tuner.

"Nunsense" is good old-fashioned comedy at its best: it is quick paced, generally raucous, occasionally touching and totally wonderful. Bravo!

"Nunsense," presented by the Nunsense Theatrical Company in association with Joseph Hoesl and Bill Crowder, at the Cherry Lane Theatre, 38 Commerce St. opened Dec. 12 for an open run.