What is the name of your tribe? "I'm not a ho."
Still, it wasn't a particularly funny or sensitive joke. And it was incorrect in its presumption that it's easy to get "tribal status" and open a casino anywhere.
I've been giving O'Brien and his staff credit for mentioning Indians, but we can't credit him for Williams's line. It was an odd thing to say, since nobody had mentioned Indians or casinos, the stage doesn't resemble a casino, and Indian casinos aren't in the news. Maybe Williams performed at a casino recently.
For more on the subject, see The 2009 TV Season So Far and The Facts About Indian Gaming.