Although Rage Against the Machine would break up less than a year after releasing their third album, 1999's The Battle of Los Angeles, the rap-metal provocateurs never softened up their approach. Famously, the January 2000 music video shoot for "Sleep Now in the Fire" featured them playing an impromptu gig outside of the New York Stock Exchange that temporarily shut down the financial institution, and their TV appearances during that era were just as feisty.
On November 3rd, 1999, the day after Battle came out, Rage took to the Late Show with David Letterman and played "Guerilla Radio" on 53rd Street in the pouring rain. After being introduced by Letterman as "a terrific rock and roll band," Tom Morello kicked into his iconic lead riff and the wily Zack de la Rocha started bouncing and hyping up the raucous crowd, who went totally apeshit while screaming the words back despite being drenched in a downpour.
It was a barn-burning performance from a band who were at the peak of their popularity, and in classic Rage form, they used their appearance on national television to make some mischief. First off, de la Rocha was sporting a "Free Mumia Abu-Jamal" shirt, and even shouted out the journalist-activist who was sitting on death row after being convicted of killing a police officer in 1982. Yelling a righteous slogan like that on live TV would probably still stir up controversy today, but it was particularly bold back in 1999.
Additionally, the frontman also used his opportunity in the spotlight to flick off the the crowd while the cameras were on him, which again, might sound quaint today, but was a genuinely transgressive action back in the conservative social climate of the late Nineties. Watch the ass-kicking performance go down above via YouTube.