Ideally you should have done a search on this site and I am sure you would have got a lot of interesting inputs.
Secondly when you put up your request, it would have helped if you shared more information about the organizational set up where you plan to implement as the engagement activities would vary depending on the background of the organization. eg. it would be very different for a manufacturing setup vs a BPO setup vs a pure marketing setup.
However to help you going I am sharing a link from this site where there have many inputs shared by various readers, and I hope you get some ideas relevant to your needs
As an HR person you may also be interested in the contents of the following Inspirational and Motivational blogs
www.actspot.wordpress.com Over 1,22,500 views and 750 followers
www.poweract.blogspot.com Over 37,500 views and 200 followers
24th August 2012 From India, Mumbai
Please take a look at my answer provided at
Best regards, Ben Simonton
Leadership is a science and so is engagement
24th August 2012 From United States, Tampa