Shredded tires to cover landfills (link)
I like simple, cheap (=energy efficient), realistically implementable (feasible) and proven eco-friendly methods such as the following: edit of 2014: sorry for the broken link, here are some fresh ones: SHREDDED TIRES A CHEAP, ENVIRONMENTALLY FRIENDLY WAY TO COVER LANDFILLS (James E. Kloeppel, Physical Sciences Editor) Shredded tires a cheap, environmentally friendly way to cover landfills (phys.org)