Here is another post which will likely never be complete.  I'm clearly past my youth, so I encourage you to add your own suggestions because I know I've missed dozens if not hundreds of ways to make Calgary better for the people who will be our next crop of leaders.  This is a bit of a mixed bag because I'm going to use a very broad definition of youth.

Youth Central aims to involve youth in all aspects of our community, while at the same time ensuring we fully value what our youth have to offer. 
Brothers Big Sisters of Calgary Linking youth with mentors, they do a fantastic job bridging generations.
Just to say the United Way is too shallow.  I know they just had their Youth Career Fair and I know they are involved with the LEAP project.  The United Way has a rich legacy of positive youth programs.
Servants Anonymous Society I am a little distant from Servants Anonymous, but have encountered them indirectly from some amazing work that they've provided.  Women suffering from (or at risk of) sexual exploitation really need Servants Anonymous.
Wood's Homes  They've been the go to for youth help in Calgary, well, since 1914.  That's amazing.
Kids Up Front Calgary They are all about getting kids out to enjoy the culture of Calgary, from sports to drama.  We want everyone to feel connected to Calgary.
The City of Calgary Youth Employment Centre  And you thought I stopped at your Stampede Breakfast just for the food?  The Youth Employment Centre is all about making that jump from school to a valuable career.
Calgary Youth Science Fair  Science is close to my heart, the Youth Science Fair passes that love of questing for knowledge to others.
Youth Link Calgary Online safety from the Calgary Police Service.  I'm an internet guy by default and I still learn.
YMCA of Calgary - Special note for their Kids in Motion Food drive happening today, Aug 16, 2012 in my own neighbourhood.
YWCA of Calgary - They help create a healthy environment for children and families across the board.
USAY Calgary  They help guide our aboriginal youth to become the strong, capable leaders into the future.

Have I covered it?  Not a chance!  Add your own below.