For those who still participate in this pastime the up-coming week will bring three heavy-duty openings. Little Godfather A1 Pacino comes to the Loeb as Richard III. Pacino, who played in the Basic Training of Pavle Hummel downtown last spring, has a terrific stage presence that will soon become justifiably renowned. Stephen Sondheim and Hal Prince do Bergman in A Little Night Music, a new musical comedy. Previews start Saturday: Vogue Magazine predicts. "It's a winner." No, No Nanette is also in town. Since this dreary musical spectacle originally glorified New York and Atlantic City back in 1925 it's been straight downhill. The coincidence is striking.

BOSTON REPERTORY THEATER. The Night Thoreau Spent in Jail. Thurs. and Sat. at 8:08; The Little Prince, Fri. at 7:07 and 9:09.

CARAVAN THEATER. Waiting for Godet at 8:30.

CHANTICLEER DINNER THEATER. No. 133 in Rowley. Stop the World I Want to Get Off. Fri. and Sat. at 9.

CHARLES PLAYHOUSE. One Flew Over the Cuckee's Nest at 7:30 mats. Sat. and Son. at 3.

COLONIAL THEATER. A Little Night Music at 7:30 mats. Thurs. and Sat. at 2. Starts Sat.

EMMANUER, CHURCH. 15 Newbery St. The Legend of Mr. Vee. Fri. and Sat. at 7 and 9.

HUB THEATRE CENTER. The Maids. Thurs. and Fri. at 8:30. Sat. at 7:30 and 9:30.

INMAN SQUARE. The Preposition at 8 and 10.

LAUGHING ALLEY. 592 Comm. Ave. Pocket Mime Chem. Thurs.-Sat, at 8:30.

LEGAL SEAFOODS. Inman Sq. Preposition Cabaret. Wed. at 9.

LOEB MAINSTAGE. Richard III at 8.

PUBLICK THEATER. 1175, Soldier's Field Rd. Ibsen's Master Builder. at 8.

SHUBERT THEATER. No, No, Nonette. Mon., Sat. at 7:30 p.m., mats. Wed. and Sat. at 2. Opens Mon.

TUFTS ARENA THEATRE. The Trojan Women at 8:15.

WILBUR THEATER. Godspell. Mon Sat. at 7:30 p.m. mats. Wed. and Sat. at 2.