Is there a secret I can pass along, based on this fun-oriented book, encouraging participants to feel that what they accomplished, " we did ourselves!”
Sure, but it's no secret.  Rather a well known strategy of sharing and teambuilding that encourages achievement without being pedagogically managed.
An evocative list - fun,choice of challenge, discussion, compassion, self-efficacy, respect, acceptance, integrity, discovery, teamwork—all integral parts of experiential/adventure education.   
This book is filled with a variety of teambuilding activities with a range of challenge levels.These activities can be used with middle and high school students, college students, and adult groups of all ages and backgrounds. 
 If you are looking at presenting FUN first, with your groups, this book is for you.
 Dr. Cavert, is a dedicated FUN magnet, and your welcoming guide to active participation.