Slack lining is a very fun and challenging "sport" that requires a lot of skill. However the cheapest slack line "kits" available are around fifty bucks, i made this one for about half of that. This instructable will show you how to set up your own slackline.
Step 1: supplies
Here is what you will need. I got all of the supplies from REI, but i am sure there are many other places that carry these things.
1 inch tubular webbing- (at least) 70 feet
carabiners - 5
carpet (1ft. by 3-5ft.)
2 trees, poles, or any two VERY sturdy upright objects