I can't remember when I didn't know of Rauschenberg's work, having probably been exposed to a few pieces in my teens on a weekend getaway to the Art Institute of Chicago, but one of my favorite experiences that encompasses Rauschenberg and his cadre of New York pals was seeing the Merce Cunningham Dance Company perform at Lincoln Center in 1999. There in one place--literally and figuratively--were Marcel Duchamp, John Cage, David Tudor, Merce Cunningham, Jasper Johns, Morton Feldman, Bob Rauschenberg and, as something of a weird bonus Mikhail Baryshnikov, Gavin Bryars and Jim O'Rourke.
The Library for Performing Arts actually has a DVD of one night that I attended in addition to other videos and printed material relating to Rauschenberg's work with the MCDC as well as his experiments in Performance Art. In addition, the Wallach Division of Art, Prints and Photographs has a plethora of material outlining Rauschenberg's entire career.
Goodbye 20th century!