What Kate is referring to was an excellent movie about "Sketchy Andy" who is the master of the slackline who occasionally likes to slackline naked. The video that initially made Andy famous was this one: http://www.youtube.com/watch?v=xYQGApmpBp4

Also, cool tricks at: http://www.youtube.com/watch?v=LUk5pafEyCc

There is a slackline at PrimeClimb where a group of mature kayakers cross train every Tuesday and Thursday eves if anyone is interested in joining.
http://www.primeclimb.com/