Make Users Get Access to Internet by Clicking on a Link (Watch video or something els

General information for the website: A User Authentication Portal for an ISP Kind of development: Customization of existing website Description of requirements/features: My client is a small ISP, they have a portal where users can use and enter their username and password to be authenticated and get access to internet. Now, in addition to above regular way to authenticate users, they want to offer another way for user to get access to internet, they want to add to the same portal, something like this: "To access internet, enter your username and password, OR: click this link (Watch this short ad), to access internet." The link could be a short video ad, or another content, they want to make the user watch that content for X minutes and not be able to escape it or close it, once X minutes finished, then a user is authenticated and gets access to internet, same way as they entered username and password. Extra notes: