One day, I ran into a group of senior level students who had started getting "lazy" when it came to homework. So I came up with the signed homework pledge. They printed and signed their lives away. One kid even went as far as providing a fingerprint (I'm stealing his identity as we speak, muhahhaha).
Anyways, I told them that if they forget to do their homework again, I was gonna fax this pledge to their moms--that got them going! Plus, I took a picture of the paper with my camera for that little bit of insurance in case it "disappeared."