Lee v. Weisman arose in 1989, when Daniel Weisman brought a lawsuit against Nathan Bishop Middle School in Providence after Rabbi Leslie Gutterman delivered a nondenominational invocation at his daughter's graduation.  Mr. Weisman had also objected three year's earlier when a Baptist minister delivered a prayer at his elder daughter's graduation from the same school.  The school did not respond to his complaint.    

Both a district court and the US Court of Appeals for the First Circuit agreed with Daniel Weisman that the use of prayer during graduation ceremonies violated the First Amendment.  But when the Supreme Court accepted the case for review, it seemed possible that the court might use it as an opportunity to revise the so-called "Lemon test" and permit prayer in schools.  The "Lemon test" is the standard that had guided the Supreme Court since it decided the case of Lemon v. Kurtzman in 1971.  Under the Lemon standard, a practice or statute was only constitutional if it had a secular purpose, neither promoted nor hurt religion, and if it did not foster "an excessive governmental entanglement with religion." By a single vote the Supreme Court in Lee v. Weisman left the Lemon standard more or less intact.

Listen to the oral argument: http://www.oyez.org/cases/1990-1999/1991/1991_90_1014
Read the decision: http://caselaw.lp.findlaw.com/scripts/getcase.pl?court=US&vol=505&invol=577