So what is the explanation of the phrase cold enough to freeze the balls off a brass monkey ?  Well, the obvious one, I believe.
( So ( ( what ( is ( ( the explanation ) ( of ( ( the phrase ) ( ( cold enough ) ( to ( ( freeze ( the balls ) ) ( off ( ( ( a ( brass ( monkey ( ? Well ) ) ) ) , ) ( the ( obvious one ) ) ) ) ) ) ) ) ) ) ) ) ( , ( I ( believe . ) ) ) ) )
(ROOT (S (IN So) (SBAR (WHNP (WP what)) (S (VP (VBZ is) (NP (NP (DT the) (NN explanation)) (PP (IN of) (NP (NP (DT the) (NN phrase)) (ADJP (JJ cold) (RB enough) (S (VP (TO to) (VP (VB freeze) (NP (DT the) (NNS balls)) (PP (IN off) (NP (NP (DT a) (NNP brass) (NNP monkey) (. ?) (NNP Well)) (, ,) (NP (DT the) (JJ obvious) (NN one)))))))))))))) (, ,) (NP (PRP I)) (VP (VBP believe)) (. .)))
Colorful language is easy to figure out.
( ( Colorful language ) ( ( is ( easy ( to ( figure out ) ) ) ) . ) )
(ROOT (S (NP (JJ Colorful) (NN language)) (VP (VBZ is) (ADJP (JJ easy) (S (VP (TO to) (VP (VB figure) (PRT (RP out))))))) (. .)))