Hallelujah! The Cantata Sirz Singers perform Handel's Messiah. 2:30 p.m., New England Conservatory's Jordan Hall, Tickets call (617) 267-6502.

More panacea for the soul, in high vocal style. Masterworks Chorale Goes to the Opera, with "Chorus of the Hebrew Slaves" from Verdi's Nabucco, the "Easter Hymn" from Mascagni's Cavalleria Rusticana and "Pilgrim's Chorus" from Wagner's Tannhauser. Sanders Theatre. 3 p.m. Tickets $28.50, $23.50 and $14.50.

The Handel and Haydn Society debut a new work, "JFK: The Voice of Peace," celebrating the founding of the Peace Corps. Symphony Hall, Boston. 3 p.m. Tickets call 266-3505.

Spiritual teacher Andrew Cohen will offer some reprieve from thesis-worries with his "Teachings of Liberation." Terrace Room, Park Plaza Hotel. 64 Arlington St. 4 p.m.

Come see Noah and his sundance kids duke it out over campus controversy. Undergraduate Council General Meeting, open to the Harvard community. Sever Hall 113.7 p.m. FREE.

Songs for a New World. Two lovers meet. A marriage ends. Someone is born. Someone dies. Our lives are filled with these moments of change, when we are suddenly forced to live our lives from a new perspective. We find ourselves in a new world. "Songs for a New World" is a musical revue, a song cycle about these moments. With a framework that ranges from a historic Spanish sailing ship in 1492 to the mythical north pole to the very real inner city of today, this fresh new pop-influenced score will excite audiences in the show's New England premiere. Adams House Pool Theatre. 13 Bow St. $7, $5 students, $4 House residents.

Scope out the celeb fashion winners and uglies at the live simulcast of the 71st Academy Awards, hosted by KISS 108's Matty in the Morning and sponsored by the Friends of the Massachussetts Film Office. The Oscars at the Fairmont Copley Plaza Hotel's Eighth Annual Academy Awards Gala Benefit lets you schmooze with members of the Boston glitterati. Fairmont Copley Plaza Hotel. $150. Call 973-8804 for invitations.

In a rare American appearance, concert pianist Marc Andre Hamelin will play works by Bach, Brahms, Alkan, Medtner and Liszt. Proceeds will benefit WHRB. Sanders Theatre. 8 p.m. Tickets $35 and $20 regular, $15 and $10 for students, reserved seating.

"Yossele Solovey," an opera based on the novel by Sholem Aleichem "The Nightingale," tells the story of the rise and fall of a wunderkind cantor in 19th century Poland. Music composed by young-looking math Professor Noam Elkies, commonly spotted working out at the MAC. Lowell House Dining Hall, 10 Holyoke Place. 8 p.m. Tickets $25 for opening night, $10 regular and $6 for students for all remaining performances.