I go mountain biking up at lehigh all the time if you are into that stuff. Also, there is the trestle to jump off near the iron pigs stadium and peace rock, which has a rope swing and a fun cliff. The only problem with peace rock is that last week somebody went into the river without knowing how to swim and drowned, so you might get in trouble for swimming there. You should also check out park 1260, which is near blue mountain, for some sick summer rail jams.