one that was hard for me to warm up to 
(ROOT (NP (NP (CD one)) (SBAR (WHNP (WDT that)) (S (VP (VBD was) (ADJP (JJ hard) (SBAR (IN for) (S (NP (PRP me)) (VP (TO to) (VP (VB warm) (PRT (RP up)) (PP (IN to))))))))))))
(ROOT (NP (NP (CD )) (SBAR (WHNP (WDT )) (S (VP (VBD ) (ADJP (JJ ) (SBAR (IN ) (S (NP (PRP )) (VP (TO ) (VP (VB ) (PRT (RP )) (PP (IN ))))))))))))