Surely the start of this slick skit is the twister that I heard as a kid is the hardest in English to say three times fast. Here’s another claim that it is indeed:
“The Sixth sick sheik’s sixth sheep’s sick” has the Guiness World Record for toughest tongue twister.
http://www.omg-facts.com/Celebs/The-Sixth-Sick-Sheiks-Sixth-Sheeps-Sick/2447#ePkwx04b1kDEmU30.99