pushing the jokes at the expense of character until things fall apart 
(ROOT (S (VP (VBG pushing) (NP (DT the) (NNS jokes)) (PP (IN at) (NP (NP (DT the) (NN expense)) (PP (IN of) (NP (NN character))))) (SBAR (IN until) (S (NP (NNS things)) (VP (VBP fall) (ADVP (RB apart))))))))
(ROOT (S (VP (VBG ) (NP (DT ) (NNS )) (PP (IN ) (NP (NP (DT ) (NN )) (PP (IN ) (NP (NN ))))) (SBAR (IN ) (S (NP (NNS )) (VP (VBP ) (ADVP (RB ))))))))