Hi ,
I am managing Employee Engagement for a large print media organization ... and have concurred employee engagement is not only fun activities, although it always begins with that and since fun is the easiest way to open up people and then lead them to start treating their work place as a fun zone to come back and work with enthused mind ,fully involved with high energy .
you may call it a old wine ( motivation) in new bottle or a latest HR fad but the purpose is to get employees energized or charged to go beyond their "job role" and work for exceeding the organization most willingly and while doing so they see their own associated growth in it.
I have found few good articles which define the EE theory ...but yet the practical aspect is still in nascent stage to come up as a tried and tested methods ( see attachment) but broad framework helps in devising a customized EE strategy and plan which would differ from one company to another.
Best Regards
Parul B Kapoor