I don't know who started it. Maybe it was Janet Reno coming on to Saturday Night Live to break up Will Ferrell's Janet Reno Dance Party. Maybe it was DeNiro or Pesci coming on to the Joe Pesci Show. It all depends if the line is crossed when the real actor confronts the impersonation or if it's really when political figures take part in their own impersonation.
But enough already. It's become de rigueur, something akin to the Fonz walking through the Cunningham's front door to the hoots and cheers of the studio audience.
Now, apparently Sarah Palin, well-aware that her moment on the national stage is nearing its end, is jumping at the opportunity to become even more of a joke by appearing on Saturday Night Live even before the end of the election season.
I'm willing to bet the joke will revolve around her not actually being folksy and full of "you betchas," akin to the twenty-year-old sketch of Reagan as mastermind.