Those seeking adventure and possibly a bit of risk taking might want to try zip lining. Though more common in faraway, mountainous areas, there are some options here in the Philadelphia area, and even more just a few hours away. While each has its own  special features, all require the use of safety harnesses and helmets and stress that participants must wear closed-toe shoes. As is common with activities involving risk, all also require a signed waiver from participants or their parents for those under 18. Spring Mountain Ski Area in Spring Mount has extended the use of its property to year round by adding zip…