Same here. I think a) It's fairly common to refer to famous people by their last names (Gates, Jobs, etc.) b) The show is "The Colbert Report", so "Colbert" w

Same here. I think a) It's fairly common to refer to famous people by their last names (Gates, Jobs, etc.) b) The show is "The Colbert Report", so "Colbert" works as a shortened version. Hence, "Did you catch Clinton on Colbert last night?" In any event this sort of usage is pretty typical.