Marilyn Manson setting fire to the stage on The Jon Stewart Show, 22 June 1995.
This was the second-to-last episode; the show had been cancelled but had to return for two final weeks of shows. Things went just a bit off the rails. The bit at the end where Jon stomps out a still-burning bit of floor whilst Manson helps himself to a piggyback ride kills me.
Batgirl on the Merv Griffin Show