Sweepstakes and drawings....do you do them? Do you win?

I used to do them, and never won so I stopped. But now getting back into coupons...I see them more and more. I was wondering...do you enter sweepstakes and drawings for "chance to win"? Have you ever won anything from those you entered? I assume "someone" has to win..somewhere in the country, but still...what are the chances? And if you sign up or fill out the registration,,,whatever it is...whether you win or loose...what do they do with that information? Do they put you on mailling lists, junk mail lists? Any thoughts here as to whether I should waste my time?