If you think you have good balance and concentration checkout this cool slacklining video filmed in a setting featuring fire and ice. I imagine getting this good on a slackline takes hours of practice. Looks like a fun way for someone to improve the balance and agility but probably best to have a soft landing underneath the slackline. This cool video is from YouTube Filmmaker extraordinaire Devin Graham and Team Supertramp and was filmed at Ice Castles.