On June 20, 1965, the Rat Pack -- Frank Sinatra, Sammy Davis and Dean Martin -- performed at a Teamsters benefit in St. Louis. Johnny Carson emceed. Proceeds from the concert went to Dismas House, a favorite charity of the legendary Teamsters leader Harold Gibbons. Wikipedia says this about Gibbons:
The St. Louis union was considered to be one of the most progressive in the United States. It initiated health care centers for members, vacation centers at Lake of the Ozarks, and militated for good pension plans for its members. Under Gibbons the Union researched and submitted plans for the desegregation of schools which was promoted by the editorial page of the St. Louis Post-Dispatch.Dismas House was a novel concept at the time -- a halfway house for ex-offenders.
You can actually buy a DVD of the concert, called "Live and Swingin'." Here's the promo copy:
LIVE AND SWINGIN’ features Frank, Sammy and Dean in prime form, dazzling the audience with their dynamic chemistry, comic camaraderie and unforgettable melodies. The live black-tie benefit performance – the first and only time cameras ever fully captured a proper "Rat Pack Summit" – was taped on Father's Day, June 20, 1965 at the Kiel Opera House in St. Louis. Emceed by Johnny Carson, this beautifully restored musical time capsule includes sets by Frank, Sammy and Dean and a rousing final performance of “Birth of the Blues.”