"Viviana a la medianoche" (literally "Viviana at midnight") is the premier Spanish-language late night talk show. The host is Viviana Gibelli, a Venezuelan actress. If you see the show she's the tall, dark one with nice cleavage (something Johnny Carson never had). With her are Tania Sanabria (the sort of frumpy woman in big glasses) and Carlos Puchi, the bassist and band leader. There's another fat guy who's a bit like Andy Richter, but I don't know his name.
Compared to American talk shows, I would say that "Viviana a la medianoche" is most like "Late Night with Conan O'Brien" in their frequent use of sketch comedy. Viviana is far, far prettier than Conan O'Brien, though.
Like most television shows on Spanish-language television, "Viviana a la medianoche" has no compunction about using sex to maintain interest -- usually in the guise of nearly-naked women. All of the "good bits" that get shown internationally, though, are fuzzed out for American television. Tant pis.
"Viviana a la medianoche" airs from midnight to 1:00 am weekdays on Univision (in the US, at least.)