I have recently discovered whoopie slings thanks to Hammock Forums and believe they are something every ultra light hiker should at least be aware of. They are basically a loop of rope where one end passes through a length of the other end. You can adjust the length of the loop by pulling the rope through but when you put tension on the outside rope it constricts around the inner rope and locks it in place. It is difficult to describe accurately so here's a link for a demo of how to make one: http://sites.google.com/a/splicesbynick.com/www/videos

There are so many applications for them. So far I have used them for my hammock suspension, guy lines and have just put some on my Golite Gust pack as compression straps (why they never put compression straps on in the first place is beyond me). I love them. They require no hardware (except hollow braid rope), are very lightweight, easily made and there is something very satisfying about the concept.

Anyone else used them for other purposes?