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Once an also-ran to the rival empires of The Tonight Show and The Late Show, Kimmel hit his stride during the brouhaha between Conan O'Brien and Jay Leno. Kimmel hosted an entire episode of his show while dressed as Leno before appearing on The Jay Leno Show to make further fun of the beleaguered host. Low blows? Certainly. But very funny, and further proof that Kimmel is stepping out as a late-night force.