tremendous -     huge, very big
sketch -            (here) short play or slight dramatic performance
teaser spot -      short scene or highlight shown at the beginning of a film or television show to attract the audience's attention
phoney -            not genuine, false (Apart from their animator, Terry Gilliam, the Pythons are British, so they just imitate the American accent in this sketch.)
comic book -      (also used as comics) a scripted series of pictures telling a story
hilarious -           very funny