Here are a couple of videos I took:
Basically, it's like trampolining on a tightrope, and it's just about the coolest thing I've ever seen. Especially when I learned from Kari that even learning to walk across the line is incredibly hard, not to mention doing tricks on it.
Here is Kari practicing her slackline walking!
While my broken foot is almost better, x-rays show that it's not completely healed. So I had to pass on the slackline myself. Argh!