I just did another one on the receipt from Burger King..... at least I KNOW that I'll get another Whopper for doing it.
The only time I ever won something was about 25 years ago. It was at a tractor place having a 'drawing' during their grand opening festivities.... you fill out the little paper and drop it in the box. The grand prize was a tractor and loader! Sure, I'll enter.....
A few weeks later, I got a call! I won the third prize!..... it was a one gallon plastic gas can......