Best way to collect emails?

I am wondering if there is a way to have people register their emails with some sort of popup.

It wouldn't be an actual popup but rather you click download now and a little box would appear and the page behind would go dim.

I dont want a popup because it will get blocked and I dont really want the user to have to go to a new page.

Any ideas, examples, advice?

 

You could use some kind of interstitial.

Or some Form entering from the side.