enough to keep you interested without coming close to bowling you over 
(ROOT (ADVP (RB enough) (S (VP (TO to) (VP (VB keep) (NP (PRP you)) (S (ADJP (JJ interested))) (PP (IN without) (S (VP (VBG coming) (ADVP (RB close) (PP (IN to) (S (VP (VBG bowling) (NP (PRP you)) (PRT (RB over))))))))))))))
(ROOT (ADVP (RB ) (S (VP (TO ) (VP (VB ) (NP (PRP )) (S (ADJP (JJ ))) (PP (IN ) (S (VP (VBG ) (ADVP (RB ) (PP (IN ) (S (VP (VBG ) (NP (PRP )) (PRT (RB ))))))))))))))