Okay, as most people now know, slacklining is walking a piece of webbing that is "tied" between two trees in order to strengthen the inner core and practice balance, especially for climbers. Since its origins and purpose, it's become somewhat of a crunchy way to show off to campsite neighbors, girls at the beach, or passersby of a front yard. Here's a video on a simple, one-person technique. It is also possible to set up...