Looking for script for: Sweepstakes/Giveaway/Enter to win

As the title says, I'd like to run a giveaway on my website. In order to enter the contest, the visitor has to enter his email address. Then one of entrants gets randomly selected and wins the prize. Something like http://gleam.io.

Does anyone know of a similar script? Preferably in PHP or basic HTML5.

THANKS BHW!

would like to know as well. been looking for 1 for a while now.