A friend of mine received a SMS telling him that he had won a prize at a contest, and to claim his prize he has to visit a website. I told him that it was most likely a scam considering that he never filled a contest form.
Reminds me of the time I had received a SMS telling me that I had won a cruise and to claim the prize I have to call a number. I had never filled a contest form, so how can I win a prize if I never gave my name? They were probably looking to get some personal infos and steal my identity.