Fawlty Towers I use with my friend almost weekly - Manuel trying to impress Basil with his "grasp" of English when Basil demands that he "FORGET IT", replies -
"…HAV-ENTUAL-LEEE!"

Classic Trek -
"Help me Spock!"
The plaintive cry of "Surak", as imitated by the Klingon Kahless. Not to be confused with "Help me Kirk!", which was going to be his follow-up act imitating Abraham Lincoln, in order to draw Spock and Kirk out of hiding. Who knew Kahless was the Rich Little of the Klingon homeworld?