Many use the jug of sand (or water) method but a hanging anything is not really a good choice..
Why is that? Well,, The hanging item can start swinging in the breeze and actually cause the tripod to tip over.
better yet a heavier weight (Say a 5 gallon bucket of water, or a jerry can) sitting on the ground with a shipping strap to the tripod to hold it.
or, if you are on the proper ground a "Claw" This is a 3 arm with 3 spikes thing that Harbor Freight used to have.. (I will check shortly). designed to hold airplanes to the ground when it gets windy.
Just did a quick search of their website, No joy. Found the company that makes it however
http://www.theclaw.com/