He says "plus ça change", short for "plus ça change, plus c'est la même chose" which is a French phrase meaning (literally) "The more it changes, the more it's the same thing". We almost never use the full phrase, just the first three words and we use it to mean something like "This is always the situation. This comes as no surprise".
In this case, he's referring to the fact that he's put little or no preparation into the part of the show that's about to happen. Clearly, this is frequently the case.
I'm having eggs for breakfast. Plus ça change. (I always have eggs for breakfast.)
She's broken up with yet another girlfriend after only three weeks. Plus ça change. (She makes a habit of doing this.)
A politician told us a lie. Plus ça change! (This is a very common occurrence.)
You can listen to two native French speakers say the phrase
HERE.
