Add a check box to new account page and checkout

I would like to know if there is a way to add a check box to the new account page and the checkout page. What I am looking at doing is offering a drawing for $XX and everyone that creates a new account will be entered (unless opt out) and offering $XX in a drawing and an entry will be given for each order (unless opt out). I would like to add a check mark to allow customers to opt out of automatic contest drawings. Is there any easy way to do this?

As this does not exist and there is not a method to capture this into the DB I would say that this will not be an easy thing to create...

Need to add a record or2 to a table in the DB and create the code to display and capture this info - after this you need to create a method and I suppose in the admin to display who and who has not seleted to participate