This script will ask the user for their Google+ ID number, then display a URL and ask them to +1 the page.
They then return to the script and click the Validate button. The script will then fetch their Google +1 page and check to see if they have +1'd the page. This is a simple check since if they have it will be the first link on the page.
If the +1 is validated it will fire a callback URL.
The script will show a URL once per user. The next time they open the script and enter their Google+ ID (remembered from last time using a cookie), it will show them a different URL until all the URLs are exhausted.
A password protected admin page will allow new URLs to be added to the rotation, with a set number of credits. Every time a +1 is validated for their page, the number of credits will be reduced by one point.
A log file should be recorded with the google +1 ID number and the date and time that each URL was validated against their account.
In the admin area it should be possible to run of a report showing all the ID numbers and timestamps for each URL in the system.