the spark of imagination that might have made it an exhilarating 
(ROOT (NP (NP (NP (DT the) (NN spark)) (PP (IN of) (NP (NN imagination)))) (SBAR (WHNP (WDT that)) (S (VP (MD might) (VP (VB have) (VP (VBN made) (S (NP (PRP it)) (NP (DT an) (NN exhilarating))))))))))
(ROOT (NP (NP (NP (DT ) (NN )) (PP (IN ) (NP (NN )))) (SBAR (WHNP (WDT )) (S (VP (MD ) (VP (VB ) (VP (VBN ) (S (NP (PRP )) (NP (DT ) (NN ))))))))))